Loading ...
Sorry, an error occurred while loading the content.
 

Re: phase noise specifications

Expand Messages
  • Scotty
    Hi Cash and all, Dealing with oscillator phase noise and PLL s is a stange marriage. If you were using a VCO without a PLL, then the total circuit phase noise
    Message 1 of 20 , Jun 23, 2005
      Hi Cash and all,
      Dealing with oscillator phase noise and PLL's is a stange
      marriage. If you were using a VCO without a PLL, then the total
      circuit phase noise will depend entirely on the noise of the VCO.
      When using a PLL, the noise contribution of the PLL usually
      determines the total phase noise. For example, if the PLL loop
      filter is 400 KHz wide, then the PLL will override the phase noise of
      the VCO up to 400 KHz. Above that, the VCO determines the noise.
      Most VCO's, even lousy cheapies, will have poor noise characteristics
      up to 10 KHz. Using an LMX 2326 PLL, with a loop bandwidth of about
      30 KHz, the phase noise at 1 KHz will be about -92 dBc/Hz. This loop
      improves the phase noise of the ROS-2150 and UMS-1283 at 1 KHz and 10
      KHz. It would not improve the phase noise of either VCO at 100 KHz,
      since the 100 KHz is above the bandwidth of the PLL loop filter.
      Therefore, the UMS would give you overall better phase noise than the
      ROS, above 30 KHz. However, once the phase noise drops below about -
      100 to -110 dBc/Hz, you probably won't see the noise on the graph.
      Also, if the noise is a least 30 dB better than the amplitude of the
      signal you are measuring, the noise will not effect your measurement.
      Which PLL has the most noise influence? Well, in the case of the
      SSA, PLL 1 is the offender. Reason: PLL 1 phase detector frequency
      is .35 MHz to .97 MHz and PLL 2 PDF is 4 MHz. PLL 2 is quieter,
      running at the higher PDF. Theoretically, the PLL 2 should be
      quieter than PLL 1 by a factor of 10log4/.35
      In the case of any system, the largest phase noise contributor will
      determine the system phase noise. Any noise contributor that is 10
      dB quieter than the worst offender, will add only 1 dB of phase noise
      to the system.
      Cheers, Scotty

      --- In spectrumanalyzer@yahoogroups.com, "S. Cash Olsen"
      <KD5SSJ@z...> wrote:
      > Scotty,
      >
      > I am evaluating the specs of some alternative VCO . How much will a
      5dB
      > better number in the phase noise make in the overall quality of the
      SSA.
      > For example:
      >
      >
      > Typ. Phase Noise 1kHz 10kHz 100kHz 1mHz
      > ROS-2150VW -70 -96 -118 -138
      > UMS-1283-R16 -75 102 -122 -143
      >
      > Is the first or second oscillator more significant in contributing
      to the
      > overall preformance?
      >
      > Would this be worth a significant price difference? I so how much,
      or would
      > there be any reason to have a high performance option at some
      premium in price.
      >
      > Cash
    • brainerd@bmi.net
      The PNP-1500-P22 looks VERY interesting. It is a complete 1000-2000 MHz synthesizer. Min step size appears to be 100KHz. But, since it uses an external
      Message 2 of 20 , Jun 23, 2005
        The PNP-1500-P22 looks VERY interesting. It is a complete 1000-2000 MHz synthesizer. Min step size
        appears to be 100KHz. But, since it uses an external clock, a DDS could be used for tiny step sizes. The
        Avnet Web site lists it for $65.39 qty 1.

        Dave - WB6DHW
        >
        > OK, Google finally came through: http://www.vco1.com/UMS.html. Looks like the part number
        > competitive with the ROS-2150VW is actually the UMS-2150-R16.
        >
        > This is a 12-volt part (as opposed to the ROS's 5-volt rating.) It puts out a lot more power (+11
        > dBm as opposed to +4), and its second-harmonicspec is about 5 dB better.Pinout *appears* to
        > be the same, although theROS's layoutis pad-oriented while the UMS data sheetseems to
        > bedevice-oriented.
        >
        > I called the Avnet 800# on their page at http://www.vco1.com/DomesticSales.htmland ordered 5
        > of them at $27.95 each via credit card. Very painless process. That is $2 cheaper than Mini-
        > Circuits' price of $29.95 each for the ROS-2150VW!
        >
        > They sound like a no-brainer replacement for anyone who is using the ROS-2150VW and can
        > supply 12V instead of 5V on Vcc. I will post some noise comparisons next week assuming the
        > partsshow up when promised.Much appreciate the tip!
        >
        > -- john, KE5FX
        >
        > -----Original Message-----
        > From: spectrumanalyzer@yahoogroups.com
        > [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of John Miles
        > Sent: Thursday, June 23, 2005 12:44 PM
        > To: spectrumanalyzer@yahoogroups.com
        > Subject: RE: [spectrumanalyzer] phase noise specifications
        >
        > Hmm. Where do you get those UMS-1283-R16 VCOs? Who makes them? Same
        > footprint as the ROS-2150VW?
        >
        > That's actually a pretty meaningful improvement, but Googleseems to befailing me.
        >
        > If you have any to sell, and they match the ROS-2150VW's frequency coverage range and PCB
        > footprint, let me know and I will PayPal you for a couple.
        >
        > -- john KE5FX
        > -----Original Message-----
        > From: spectrumanalyzer@yahoogroups.com
        > [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
        > Sent: Thursday, June 23, 2005 12:37 PM
        > To: spectrumanalyzer@yahoogroups.com
        > Subject: [spectrumanalyzer] phase noise specifications
        >
        > Scotty,
        >
        > I am evaluating the specs of some alternative VCO . How much will a 5dB
        > better number in the phase noise make in the overall quality of the SSA.
        > For example:
        >
        >
        > Typ. Phase Noise 1kHz 10kHz 100kHz 1mHz
        > ROS-2150VW -70 -96 -118 -138
        > UMS-1283-R16 -75 102 -122 -143
        >
        > Is the first or second oscillator more significant in contributing to the
        > overall preformance?
        >
        > Would this be worth a significant price difference? I so how much, or
        > would
        > there be any reason to have a high performance option at some premium in
        > price.
        >
        > Cash
        >
        >
        >
        > Yahoo! Groups Links
        > * To visit your group on the web, go to:
        > http://groups.yahoo.com/group/spectrumanalyzer/
        >
        > * To unsubscribe from this group, send an email to:
        > spectrumanalyzer-unsubscribe@yahoogroups.com
        >
        > * Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
        >
      • John Miles
        Yeah, I saw that. It is pretty quiet, too -- they claim -100 dBc/Hz at 10 kHz, which is a good 7-8 dB better than I tend to get out of my hybrid DDS PLL
        Message 3 of 20 , Jun 23, 2005
          Yeah, I saw that.  It is pretty quiet, too -- they claim -100 dBc/Hz at 10 kHz, which is a good 7-8 dB better than I tend to get out of my hybrid DDS PLL boards.
           
          Mine is about the same at 100 kHz from the carrier (~-120 dBc/Hz versus -118 for theirs), and they might be a few dB better by 1 MHz. 
           
          Driving it with a DDS followed by a crystal filter should work very well indeed.  Or you could simply move your fine-tuning LO farther down the signal chain.  If they live up to their billing, these parts should make great front-end synthesizers.  In fact, -100 dBc/Hz at 10 kHz is just about exactly where the HP 8566 and Tek 49x analyzers end up limited by their own YIG-tuned LOs. 
           
          They are claiming -100 dBc/Hz at 1 kHz as well, which is outstanding.  I can only swing about -84 dBc/Hz at 1 kHz!
           
          -- john KE5FX
          -----Original Message-----
          From: spectrumanalyzer@yahoogroups.com [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of brainerd@...
          Sent: Thursday, June 23, 2005 8:55 PM
          To: spectrumanalyzer@yahoogroups.com
          Subject: RE: [spectrumanalyzer] phase noise specifications

            The PNP-1500-P22 looks VERY interesting.  It is a complete 1000-2000 MHz synthesizer.  Min step size
          appears to be 100KHz.  But, since it uses an external clock, a DDS could be used for tiny step sizes.  The
          Avnet Web site lists it for $65.39 qty 1.

          Dave - WB6DHW
          >
          > OK, Google finally came through: http://www.vco1.com/UMS.html. Looks like the part number
          > competitive with the ROS-2150VW is actually the UMS-2150-R16.
          >
          > This is a 12-volt part (as opposed to the ROS's 5-volt rating.) It puts out a lot more power (+11
          > dBm as opposed to +4), and its second-harmonicspec is about 5 dB better.Pinout *appears* to
          > be the same, although theROS's layoutis pad-oriented while the UMS data sheetseems to
          > bedevice-oriented.
          >
          > I called the Avnet 800# on their page at http://www.vco1.com/DomesticSales.htmland ordered 5
          > of them at $27.95 each via credit card. Very painless process. That is $2 cheaper than Mini-
          > Circuits' price of $29.95 each for the ROS-2150VW!
          >
          > They sound like a no-brainer replacement for anyone who is using the ROS-2150VW and can
          > supply 12V instead of 5V on Vcc. I will post some noise comparisons next week assuming the
          > partsshow up when promised.Much appreciate the tip!
          >
          > -- john, KE5FX
          >
          >     -----Original Message-----
          >     From: spectrumanalyzer@yahoogroups.com
          >     [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of John Miles
          >     Sent: Thursday, June 23, 2005 12:44 PM
          >     To: spectrumanalyzer@yahoogroups.com
          >     Subject: RE: [spectrumanalyzer] phase noise specifications
          >    
          >     Hmm. Where do you get those UMS-1283-R16 VCOs? Who makes them? Same
          >     footprint as the ROS-2150VW?
          >
          > That's actually a pretty meaningful improvement, but Googleseems to befailing me.
          >
          > If you have any to sell, and they match the ROS-2150VW's frequency coverage range and PCB
          > footprint, let me know and I will PayPal you for a couple.
          >
          > -- john KE5FX
          >     -----Original Message-----
          >     From: spectrumanalyzer@yahoogroups.com
          >     [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
          >     Sent: Thursday, June 23, 2005 12:37 PM
          >     To: spectrumanalyzer@yahoogroups.com
          >     Subject: [spectrumanalyzer] phase noise specifications
          >    
          >     Scotty,
          >    
          >     I am evaluating the specs of some alternative VCO . How much will a 5dB
          >     better number in the phase noise make in the overall quality of the SSA.
          >     For example:
          >    
          >    
          >     Typ. Phase Noise 1kHz 10kHz 100kHz 1mHz
          >     ROS-2150VW  -70 -96 -118 -138
          >     UMS-1283-R16 -75 102 -122 -143
          >    
          >     Is the first or second oscillator more significant in contributing to the
          >     overall preformance?
          >    
          >     Would this be worth a significant price difference? I so how much, or
          >     would
          >     there be any reason to have a high performance option at some premium in
          >     price.
          >    
          >     Cash
          >
          >
          >
          > Yahoo! Groups Links
          > *   To visit your group on the web, go to:
          >     http://groups.yahoo.com/group/spectrumanalyzer/
          >    
          > *   To unsubscribe from this group, send an email to:
          >     spectrumanalyzer-unsubscribe@yahoogroups.com
          >    
          > *   Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
          >


        • swetterlin
          Regarding the PNP-1500-P22. How do they get phase noise measurements of -90,-100 ... when their graphs all show the noise level at 75-80 db below the peak?
          Message 4 of 20 , Jun 24, 2005
            Regarding the PNP-1500-P22. How do they get phase noise measurements
            of -90,-100 ... when their graphs all show the noise level at 75-80
            db below the peak?

            Also, the level of spurs may be more important than the phase noise,
            since this part would be used broadband and couln't be run through a
            narrowband filter.

            Still, it is nice to see that someone is combining the PLL and VCO in
            a single unit with a simple interface.

            Sam W
          • John Miles
            Composite (AM+PM) noise is equal to the observed level on the graph minus 10*log(bandwidth), plus small fudge factors to account for the equivalent noise
            Message 5 of 20 , Jun 24, 2005
              Composite (AM+PM) noise is equal to the observed level on the graph minus 10*log(bandwidth), plus small fudge factors to account for the equivalent noise bandwidth of the analyzer's filter and the noise response characteristic of the video detector. 
               
              The filter and detector correction factors amount to a couple dB and are often conveniently ignored because they make your noise reading look worse.  But nobody ignores the 10*log(RBW) factor because (a) it's very large, and (b) it makes your reading look *better*. :-)
               
              Most commercial analyzers can do the calculation for you. 
               
              Their spur content appears to be excellent, too.  Wish I'd noticed these parts before I ordered the others; I'd have thrown one in just to see if it lives up to its billing...
               
              -- john, KE5FX
              -----Original Message-----
              From: spectrumanalyzer@yahoogroups.com [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of swetterlin
              Sent: Friday, June 24, 2005 4:43 AM
              To: spectrumanalyzer@yahoogroups.com
              Subject: [spectrumanalyzer] Re: phase noise specifications

              Regarding the PNP-1500-P22.  How do they get phase noise measurements
              of -90,-100 ...  when their graphs all show the noise level at 75-80
              db below the peak?

              Also, the level of spurs may be more important than the phase noise,
              since this part would be used broadband and couln't be run through a
              narrowband filter.

              Still, it is nice to see that someone is combining the PLL and VCO in
              a single unit with a simple interface.

              Sam W


            • Scotty
              Hi Swetterlin and all, When looking at a phase noise graph, always look to see what resolution bandwidth in which they are taking the measurement. You must
              Message 6 of 20 , Jun 24, 2005
                Hi Swetterlin and all,
                When looking at a phase noise graph, always look to see what
                resolution bandwidth in which they are taking the measurement. You
                must convert the measurement BW to a 1 Hz BW for a dBc/Hz number. For
                example, their graph is claiming a phase noise -101.3 dBm/Hz at 10
                KHz. They have their Res BW at 300 Hz. Convert 300 Hz to 1 Hz: 300
                Hz bw= 10Log300= 24.77 This means that the noise power in a 300 Hz
                bandwidth is 24.77 dB greater than the noise measured in a 1 Hz
                bandwidth. The plotted graph line is about -77 dBc at 10 KHz.
                Subtract the 1 Hz bw (in dB) from the graph measurement: -77dBc -
                24.7 dB = -101.77 dBc/Hz. This is how they get their correct number.
                If anyone who wishes to buy and construct this PLL approach using
                the PNP-1500-P22, I will add this option to the software for the
                SSA's. Let me know. Wouldn't mind trying this myself, if I had one,
                of course. You wanna buy several and send me a sample (grin)?
                Cheers, Scotty

                --- In spectrumanalyzer@yahoogroups.com, "swetterlin"
                <swetterlin@m...> wrote:
                > Regarding the PNP-1500-P22. How do they get phase noise measurements
                > of -90,-100 ... when their graphs all show the noise level at 75-80
                > db below the peak?
                >
                > Also, the level of spurs may be more important than the phase noise,
                > since this part would be used broadband and couln't be run through a
                > narrowband filter.
                >
                > Still, it is nice to see that someone is combining the PLL and VCO in
                > a single unit with a simple interface.
                >
                > Sam W
              • swetterlin
                Hi Scotty I tried out the SRD approach and thought I was getting marginal phase noise quality with -85dbc at 1kHz, -95 at 10kHz, but it turns out with the
                Message 7 of 20 , Jun 24, 2005
                  Hi Scotty
                  I tried out the SRD approach and thought I was getting marginal phase
                  noise quality with -85dbc at 1kHz, -95 at 10kHz, but it turns out with
                  the bandwidth correction the real numbers are -100 and -110. Not so bad.

                  Your explanation makes sense for truly random noise--on a spectrum
                  analyzer, as you narrow the RBW the noise drops. But as for spurs,
                  which are not random but represent noise at precise frequencies, the
                  peak level will not drop as you narrow the RBW--you will just get a
                  narrower and narrower peak and the peak will start to stick out well
                  above the surrounding noise level. Their data sheet states spurs are
                  -60 to -80 dbc depending on step size. Doesn't that level of spurs
                  create a problem? For example, if you are tuned to 500MHz and there
                  is a -60dbc spur at 1MHz above the tuned LO signal, your IF signal
                  will contain a small piece of any signal at 501MHz. If there is no
                  actual signal at 500 but a 0dbm signal at 501, it will appear as
                  though there is a -60dbm signal at 500MHz.

                  Sam W

                  --- In spectrumanalyzer@yahoogroups.com, "Scotty" <wsprowls@y...> wrote:
                  > Hi Swetterlin and all,
                  > When looking at a phase noise graph, always look to see what
                  > resolution bandwidth in which they are taking the measurement. You
                  > must convert the measurement BW to a 1 Hz BW for a dBc/Hz number. > >
                • william sprowls
                  Hi Swetterlin, True, spurs are not noise and are treated as real signals in a spectrum analyzer. If a local oscillator has spurs, they are always relative to
                  Message 8 of 20 , Jun 24, 2005
                    Hi Swetterlin,
                    True, spurs are not noise and are treated as real
                    signals in a spectrum analyzer. If a local oscillator
                    has spurs, they are always relative to the frequency
                    of oscillation. Most spurs created within a PLL are
                    harmonics of the phase detector frequency (PDF). If
                    the PLL's PDF is running at 300 KHz and the PLL's VCO
                    is at 1000 MHz, there will be two spurs, 300 KHz above
                    and below the carrier frequency of 1000 MHz, or
                    999.700 MHz and 1000.300 MHz. There will also be
                    spurs at the harmonics of 300 KHz away from the
                    carrier. For example, 1000.3000 MHz (1st harmonic),
                    1000.600 MHz (second harmonic), 1001.200 MHz (third
                    harmonic), etc. As you go further away from the
                    carrier, these spurs will become lower in amplitude.
                    Theoretically, if a PLL had a perfect loop bandwidth,
                    that is, any frequency above its 0 gain crossover had
                    high attenuation, there would be no PDF spurs at all.
                    In most cases, and in the SSA, the first PDF spur is
                    the only one that can be seen. In the SSA's PLL 1,
                    with a PDF of 356 KHz, the PDF first harmonic spur is
                    about -70 dBc (relative to the carrier).
                    Now, does this create a problem in measurement?
                    When there is a real signal entering a mixing action
                    with a local oscillator (that has spurs), the
                    resulting I.F. signal will have the identical spur
                    relationship. Example: If we have a 1000 MHz LO (with
                    spurs at 999.7 MHz and 1000.3 MHz) and it is mixed
                    with a real signal at 1050 MHz (perfect signal with no
                    noise or spurs). The IF freq of 50 MHz will have
                    spurs at 49.7 MHz and 50.3 MHz. The IF spur
                    amplitudes, relative to the carrier, will have the
                    same spur amplitude relationship as it was in the LO.
                    In the case of the SSA, the spurs on each side of the
                    IF signal will be -70 dBc. So, yes, these spurs can
                    cause confusion if you are not prepared to deal with
                    them.
                    If the LO is mixing with no other signal, there will
                    be no spurs created in the IF. As a matter of fact,
                    the only thing in the IF will be converted noise.
                    Remember, PDF spurs are relative to the carrier. A
                    PLL running at a PDF of 300 KHz will NOT produce spurs
                    at 300 KHz (relative to 0 MHz) and its harmonics.
                    That is, there will be no created spurs at 300 KHz,
                    600 KHz, etc. Therefore, if no signal enters the SSA,
                    there will not be a PDF spur shown on the Graph.
                    In the case of the SSA, the dynamic range
                    (amplitude) is about 80 dB. If a very large (and
                    clean) signal entered the SSA and created a maximum
                    resonse at the top of the scale, the PDF spurs would
                    be 70 dB below that. You would see the spur responses
                    in the lowest portion of the scale, along with the
                    baseline noise.
                    I am in the process of changing the SSA software to
                    include a "spur test" button. When clicked, the PDF
                    will change in frequency. Real signals will remain at
                    the same position of the graph, spurs will move or
                    dissappear. It is for the operator who is ever in
                    doubt whether a signal is real, or it is a spur
                    created within the SSA.
                    Cheers, Scotty



                    --- swetterlin <swetterlin@...> wrote:

                    > Hi Scotty
                    > I tried out the SRD approach and thought I was
                    > getting marginal phase
                    > noise quality with -85dbc at 1kHz, -95 at 10kHz, but
                    > it turns out with
                    > the bandwidth correction the real numbers are -100
                    > and -110. Not so bad.
                    >
                    > Your explanation makes sense for truly random
                    > noise--on a spectrum
                    > analyzer, as you narrow the RBW the noise drops.
                    > But as for spurs,
                    > which are not random but represent noise at precise
                    > frequencies, the
                    > peak level will not drop as you narrow the RBW--you
                    > will just get a
                    > narrower and narrower peak and the peak will start
                    > to stick out well
                    > above the surrounding noise level. Their data sheet
                    > states spurs are
                    > -60 to -80 dbc depending on step size. Doesn't that
                    > level of spurs
                    > create a problem? For example, if you are tuned to
                    > 500MHz and there
                    > is a -60dbc spur at 1MHz above the tuned LO signal,
                    > your IF signal
                    > will contain a small piece of any signal at 501MHz.
                    > If there is no
                    > actual signal at 500 but a 0dbm signal at 501, it
                    > will appear as
                    > though there is a -60dbm signal at 500MHz.
                    >
                    > Sam W
                    >
                    > --- In spectrumanalyzer@yahoogroups.com, "Scotty"
                    > <wsprowls@y...> wrote:
                    > > Hi Swetterlin and all,
                    > > When looking at a phase noise graph, always look
                    > to see what
                    > > resolution bandwidth in which they are taking the
                    > measurement. You
                    > > must convert the measurement BW to a 1 Hz BW for a
                    > dBc/Hz number. > >
                    >
                    >
                    >




                    ____________________________________________________
                    Yahoo! Sports
                    Rekindle the Rivalries. Sign up for Fantasy Football
                    http://football.fantasysports.yahoo.com
                  • John Miles
                    Well, the UMS-2150-R16 VCOs showed up today from Avnet. Very good service from them, although I still don t know how much I paid for S&H, which scares me!
                    Message 9 of 20 , Jun 27, 2005
                      Well, the UMS-2150-R16 VCOs showed up today from Avnet.  Very good service from them, although I still don't know how much I paid for S&H, which scares me!
                       
                      Composite noise comparisons in my hybrid DDS/PLL synth are as follows.  Blue = the UMS part, purple = the Mini-Circuits ROS-2150VW that I normally use for coverage between 1-2 GHz.
                       
                       
                      The marker is at 10 kHz, 3 kHz, and 300 Hz from the 1200-MHz carrier, respectively.  Loop bandwidth is approximately 2500 Hz.
                       
                      Executive summary is that the UMS VCO's performance is close to identical to the ROS part within and near the loop bandwidth (as expected), but approximately 3 dB *worse* at 10 kHz.  This was NOT expected, given its data-sheet specs.
                       
                      Actual results at 10 kHz were -90.3 dBc/Hz for the ROS-2150 and -87.3 dBc/Hz for the UMS-2150.
                       
                      This is not a scientific test -- it only used one sample, and there's a 300-mA DDS chip right next to the PLL circuit on my board that could theoretically raise the noise floor of every part on the board.  However, I did conduct three additional tests to sanity-check the 10-kHz result. 
                       
                      First, I redesigned the loop filter for 1250 Hz, to make sure that the measurement at the 10-kHz offset was being made well outside the loop bandwidth.  That earned an improvement of about 3 dB, pretty much as expected.  (The equations I use for this synthesizer tend to result in a somewhat wider-than-predicted loop bandwidth.)  The two VCOs were now competitive at 10 kHz from the carrier, but at the cost of a large (4.7 uF) cap in the loop filter and significantly-increased lock times.
                       
                      Next, I disabled the AD9852 DDS by yanking its clock signal, and fed a 10.7-MHz reference signal directly into the PLL from an HP 8657A signal generator.  This had no effect on the 10-kHz noise level.
                       
                      Finally, recognizing that the higher power output from the UMS VCO was exceeding the recommended input power spec of the ADF4112 PLL chip's prescaler, I used a larger voltage divider ratio between the VCO and PLL chip to drop the signal by several dB.  This had no effect on either the in-band or out-of-band noise.
                       
                      I can't condemn the UMS part with 100% certainty, of course, but based on my tests, it offers no significant noise advantage over the Mini-Circuits ROS-2150VW.
                       
                      -- john, KE5FX
                      -----Original Message-----
                      From: John Miles [mailto:jmiles@...]
                      Sent: Thursday, June 23, 2005 1:12 PM
                      To: spectrumanalyzer@yahoogroups.com
                      Subject: RE: [spectrumanalyzer] phase noise specifications

                      OK, Google finally came through: http://www.vco1.com/UMS.html .  Looks like the part number competitive with the ROS-2150VW is actually the UMS-2150-R16.
                       
                      This is a 12-volt part (as opposed to the ROS's 5-volt rating.)  It puts out a lot more power (+11 dBm as opposed to +4), and its second-harmonic spec is about 5 dB better.  Pinout *appears* to be the same, although the ROS's layout is pad-oriented while the UMS data sheet seems to be device-oriented.
                       
                      I called the Avnet 800# on their page at http://www.vco1.com/DomesticSales.html and ordered 5 of them at $27.95 each via credit card.  Very painless process.  That is $2 cheaper than Mini-Circuits' price of $29.95 each for the ROS-2150VW! 
                       
                      They sound like a no-brainer replacement for anyone who is using the ROS-2150VW and can supply 12V instead of 5V on Vcc.  I will post some noise comparisons next week assuming the parts show up when promised.  Much appreciate the tip!
                       
                      -- john, KE5FX
                       
                      -----Original Message-----
                      From: spectrumanalyzer@yahoogroups.com [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of John Miles
                      Sent: Thursday, June 23, 2005 12:44 PM
                      To: spectrumanalyzer@yahoogroups.com
                      Subject: RE: [spectrumanalyzer] phase noise specifications

                      Hmm.  Where do you get those UMS-1283-R16 VCOs?  Who makes them?  Same footprint as the ROS-2150VW? 
                       
                      That's actually a pretty meaningful improvement, but Google seems to be failing me. 
                       
                      If you have any to sell, and they match the ROS-2150VW's frequency coverage range and PCB footprint, let me know and I will PayPal you for a couple. 
                       
                      -- john KE5FX
                      -----Original Message-----
                      From: spectrumanalyzer@yahoogroups.com [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
                      Sent: Thursday, June 23, 2005 12:37 PM
                      To: spectrumanalyzer@yahoogroups.com
                      Subject: [spectrumanalyzer] phase noise specifications

                      Scotty,

                      I am evaluating the specs of some alternative VCO . How much will a 5dB
                      better number in the phase noise make in the overall quality of the SSA.
                      For example:


                      Typ. Phase Noise      1kHz      10kHz      100kHz      1mHz
                      ROS-2150VW            -70      -96      -118      -138
                      UMS-1283-R16      -75      102      -122      -143

                      Is the first or second oscillator more significant in contributing to the
                      overall preformance?

                      Would this be worth a significant price difference? I so how much, or would
                      there be any reason to have a high performance option at some premium in price.

                      Cash

                    • S. Cash Olsen
                      Great work John, so much for that idea. Cash
                      Message 10 of 20 , Jun 28, 2005
                        Great work John, so much for that idea.

                        Cash
                      • John Miles
                        There are still some things I want to check -- these VCOs have more tuning sensitivity than the ROS parts, so I want to make sure I m not limited by opamp
                        Message 11 of 20 , Jun 28, 2005
                          There are still some things I want to check -- these VCOs have more tuning sensitivity than the ROS parts, so I want to make sure I'm not limited by opamp output noise.  I use the LT1677, which is pretty quiet, but you never know until you crunch the numbers.  More later, maybe...
                           
                          -- john, KE5FX
                          -----Original Message-----
                          From: spectrumanalyzer@yahoogroups.com [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
                          Sent: Tuesday, June 28, 2005 6:32 AM
                          To: spectrumanalyzer@yahoogroups.com
                          Subject: [spectrumanalyzer] UMS-2150 VCO versus ROS-2150VW

                          Great work John, so much for that idea.

                          Cash

                        • John Miles
                          I messed around with the synth a little more this morning, and was able to get the 10 kHz noise down to -94.3 dBc/Hz by redesigning it with a passive loop
                          Message 12 of 20 , Jun 28, 2005
                            I messed around with the synth a little more this morning, and was able to
                            get the 10 kHz noise down to -94.3 dBc/Hz by redesigning it with a passive
                            loop filter via ADIsimPLL. But that seems to be as good as I can do,
                            regardless of the reference (DDS, HP 8657A, or 10 MHz from the back of the
                            8566).

                            These parts may reach their stated specs under absolutely-ideal conditions,
                            but I was unable to come anywhere near those conditions on the bench.
                            Frankly, some aspects of their claims (e.g., improving the phase noise while
                            at the same time increasing the KVco MHz/V figure) don't pass the sniff
                            test. It would be interesting to see an eval board from Universal Microwave
                            that would allow independent verification.

                            Cash, I *definitely* would encourage you to confirm or dispute my results
                            with your boards, rather than giving up. Send me your snail-mail address,
                            if you like, and I'll send you one of the VCOs. I have four left, and
                            they're unlikely to get used as long as I don't know why the ROS-2150VW
                            beats them!

                            -- john, KE5FX


                            -----Original Message-----
                            From: John Miles [mailto:jmiles@...]
                            Sent: Tuesday, June 28, 2005 7:58 AM
                            To: spectrumanalyzer@yahoogroups.com
                            Subject: RE: [spectrumanalyzer] UMS-2150 VCO versus ROS-2150VW


                            There are still some things I want to check -- these VCOs have more tuning
                            sensitivity than the ROS parts, so I want to make sure I'm not limited by
                            opamp output noise. I use the LT1677, which is pretty quiet, but you never
                            know until you crunch the numbers. More later, maybe...

                            -- john, KE5FX
                            -----Original Message-----
                            From: spectrumanalyzer@yahoogroups.com
                            [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
                            Sent: Tuesday, June 28, 2005 6:32 AM
                            To: spectrumanalyzer@yahoogroups.com
                            Subject: [spectrumanalyzer] UMS-2150 VCO versus ROS-2150VW


                            Great work John, so much for that idea.

                            Cash
                          • S. Cash Olsen
                            John and group, I was looking for a suitable substitute for the OP27 and came up with the TLE2141CD. Any comments about this part, has anyone tried this one?
                            Message 13 of 20 , Jun 28, 2005
                              John and group,

                              I was looking for a suitable substitute for the OP27 and came up with the
                              TLE2141CD. Any comments about this part, has anyone tried this one?

                              At 08:57 AM 6/28/2005, you wrote:
                              >There are still some things I want to check -- these VCOs have more tuning
                              >sensitivity than the ROS parts, so I want to make sure I'm not limited by
                              >opamp output noise. I use the LT1677, which is pretty quiet, but you
                              >never know until you crunch the numbers. More later, maybe...
                              >
                              >-- john, KE5FX
                              >-----Original Message-----
                              >From: spectrumanalyzer@yahoogroups.com
                              >[mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
                              >Sent: Tuesday, June 28, 2005 6:32 AM
                              >To: spectrumanalyzer@yahoogroups.com
                              >Subject: [spectrumanalyzer] UMS-2150 VCO versus ROS-2150VW
                              >
                              >Great work John, so much for that idea.
                              >
                              >Cash
                              >
                              ><?---- LSpots keywords ?><?---- HM ADS ?> <?---- LSpots keywords ?> <?----
                              >HM ADS ?>
                              >
                              >----------
                              >YAHOO! GROUPS LINKS
                              >
                              > Visit your group
                              > "<http://groups.yahoo.com/group/spectrumanalyzer>spectrumanalyzer" on the web.
                              >
                              > To unsubscribe from this group, send an email to:
                              >
                              ><mailto:spectrumanalyzer-unsubscribe@yahoogroups.com?subject=Unsubscribe>spectrumanalyzer-unsubscribe@yahoogroups.com
                              >
                              >
                              > Your use of Yahoo! Groups is subject to the
                              > <http://docs.yahoo.com/info/terms/>Yahoo! Terms of Service.
                              >
                              >----------
                            • John Miles
                              Looks OK, but I ve never heard of it; what s the advantage over the OP(A)27? The LT1677 is the best all-around low-noise part I ve seen so far. It is a
                              Message 14 of 20 , Jun 28, 2005
                                Looks OK, but I've never heard of it; what's the advantage over the OP(A)27?  The LT1677 is the best all-around low-noise part I've seen so far.  It is a rail-to-rail OP27.
                                 
                                -- john, KE5FX
                                -----Original Message-----
                                From: spectrumanalyzer@yahoogroups.com [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
                                Sent: Tuesday, June 28, 2005 4:37 PM
                                To: spectrumanalyzer@yahoogroups.com
                                Subject: RE: [spectrumanalyzer] UMS-2150 VCO versus ROS-2150VW

                                John and group,

                                I was looking for a suitable substitute for the OP27 and came up with the
                                TLE2141CD. Any comments about this part, has anyone tried this one?

                                At 08:57 AM 6/28/2005, you wrote:
                                >There are still some things I want to check -- these VCOs have more tuning
                                >sensitivity than the ROS parts, so I want to make sure I'm not limited by
                                >opamp output noise.  I use the LT1677, which is pretty quiet, but you
                                >never know until you crunch the numbers.  More later, maybe...
                                >
                                >-- john, KE5FX
                                >-----Original Message-----
                                >From: spectrumanalyzer@yahoogroups.com
                                >[mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
                                >Sent: Tuesday, June 28, 2005 6:32 AM
                                >To: spectrumanalyzer@yahoogroups.com
                                >Subject: [spectrumanalyzer] UMS-2150 VCO versus ROS-2150VW
                                >
                                >Great work John, so much for that idea.
                                >
                                >Cash
                                >
                                ><?---- LSpots keywords ?><?---- HM ADS ?> <?---- LSpots keywords ?> <?----
                                >HM ADS ?>
                                >
                                >----------
                                >YAHOO! GROUPS LINKS
                                >
                                >  Visit your group
                                > "<http://groups.yahoo.com/group/spectrumanalyzer>spectrumanalyzer" on the web.
                                >
                                >  To unsubscribe from this group, send an email to:
                                >
                                ><mailto:spectrumanalyzer-unsubscribe@yahoogroups.com?subject=Unsubscribe>spectrumanalyzer-unsubscribe@yahoogroups.com
                                >
                                >
                                >  Your use of Yahoo! Groups is subject to the
                                > <http://docs.yahoo.com/info/terms/>Yahoo! Terms of Service.
                                >
                                >----------

                              • S. Cash Olsen
                                John, Well I didn t think to look and see what you were using. The OP27 is obsolete and is not or soon will not be readily available. I ll make the LT1677 a
                                Message 15 of 20 , Jun 28, 2005
                                  John,

                                  Well I didn't think to look and see what you were using. The OP27 is obsolete and is not or soon will not be readily available. I'll make the LT1677 a replacement part for the OP27.

                                  Thanks,

                                  Cash

                                  At 05:46 PM 6/28/2005, you wrote:
                                  Looks OK, but I've never heard of it; what's the advantage over the OP(A)27?  The LT1677 is the best all-around low-noise part I've seen so far.  It is a rail-to-rail OP27.
                                   
                                  -- john, KE5FX
                                  -----Original Message-----
                                  From: spectrumanalyzer@yahoogroups.com [ mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
                                  Sent: Tuesday, June 28, 2005 4:37 PM
                                  To: spectrumanalyzer@yahoogroups.com
                                  Subject: RE: [spectrumanalyzer] UMS-2150 VCO versus ROS-2150VW

                                  John and group,

                                  I was looking for a suitable substitute for the OP27 and came up with the
                                  TLE2141CD. Any comments about this part, has anyone tried this one?

                                  At 08:57 AM 6/28/2005, you wrote:
                                  >There are still some things I want to check -- these VCOs have more tuning
                                  >sensitivity than the ROS parts, so I want to make sure I'm not limited by
                                  >opamp output noise.  I use the LT1677, which is pretty quiet, but you
                                  >never know until you crunch the numbers.  More later, maybe...
                                  >
                                  >-- john, KE5FX
                                  >-----Original Message-----
                                  >From: spectrumanalyzer@yahoogroups.com
                                  >[ mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
                                  >Sent: Tuesday, June 28, 2005 6:32 AM
                                  >To: spectrumanalyzer@yahoogroups.com
                                  >Subject: [spectrumanalyzer] UMS-2150 VCO versus ROS-2150VW
                                  >
                                  >Great work John, so much for that idea.
                                  >
                                  >Cash
                                  >
                                  ><?---- LSpots keywords ?><?---- HM ADS ?> <?---- LSpots keywords ?> <?----
                                  >HM ADS ?>
                                  >
                                  >----------
                                  >YAHOO! GROUPS LINKS
                                  >
                                  >  Visit your group
                                  > "< http://groups.yahoo.com/group/spectrumanalyzer >spectrumanalyzer" on the web.
                                  >
                                  >  To unsubscribe from this group, send an email to:
                                  >
                                  >< mailto:spectrumanalyzer-unsubscribe@yahoogroups.com?subject=Unsubscribe >spectrumanalyzer-unsubscribe@yahoogroups.com
                                  >
                                  >
                                  >  Your use of Yahoo! Groups is subject to the
                                  > < http://docs.yahoo.com/info/terms/>Yahoo! Terms of Service.
                                  >
                                  >----------

                                  <?---- LSpots keywords ?><?---- HM ADS ?> <?---- LSpots keywords ?> <?---- HM ADS ?>

                                  YAHOO! GROUPS LINKS

                                   Visit your group " spectrumanalyzer" on the web.
                                   
                                   To unsubscribe from this group, send an email to:
                                    spectrumanalyzer-unsubscribe@yahoogroups.com
                                   
                                   Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

                                • John Miles
                                  Hmm, I was thinking that Scotty s and my discussion about OP27 replacements was on the SA list, but it looks like we never publicized it. :) Yes, as far as
                                  Message 16 of 20 , Jun 28, 2005
                                    Hmm, I was thinking that Scotty's and my discussion about OP27 replacements was on the SA list, but it looks like we never publicized it. :)  Yes, as far as I'm aware, the LT1677 is the preferred replacement.  Scotty, did you ever find anything you liked better?
                                     
                                    -- john, KE5FX
                                    -----Original Message-----
                                    From: spectrumanalyzer@yahoogroups.com [mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
                                    Sent: Tuesday, June 28, 2005 5:16 PM
                                    To: spectrumanalyzer@yahoogroups.com
                                    Subject: RE: [spectrumanalyzer] UMS-2150 VCO versus ROS-2150VW

                                    John,

                                    Well I didn't think to look and see what you were using. The OP27 is obsolete and is not or soon will not be readily available. I'll make the LT1677 a replacement part for the OP27.

                                    Thanks,

                                    Cash

                                    At 05:46 PM 6/28/2005, you wrote:
                                    Looks OK, but I've never heard of it; what's the advantage over the OP(A)27?  The LT1677 is the best all-around low-noise part I've seen so far.  It is a rail-to-rail OP27.
                                     
                                    -- john, KE5FX
                                    -----Original Message-----
                                    From: spectrumanalyzer@yahoogroups.com [ mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
                                    Sent: Tuesday, June 28, 2005 4:37 PM
                                    To: spectrumanalyzer@yahoogroups.com
                                    Subject: RE: [spectrumanalyzer] UMS-2150 VCO versus ROS-2150VW

                                    John and group,

                                    I was looking for a suitable substitute for the OP27 and came up with the
                                    TLE2141CD. Any comments about this part, has anyone tried this one?

                                    At 08:57 AM 6/28/2005, you wrote:
                                    >There are still some things I want to check -- these VCOs have more tuning
                                    >sensitivity than the ROS parts, so I want to make sure I'm not limited by
                                    >opamp output noise.  I use the LT1677, which is pretty quiet, but you
                                    >never know until you crunch the numbers.  More later, maybe...
                                    >
                                    >-- john, KE5FX
                                    >-----Original Message-----
                                    >From: spectrumanalyzer@yahoogroups.com
                                    >[ mailto:spectrumanalyzer@yahoogroups.com]On Behalf Of S. Cash Olsen
                                    >Sent: Tuesday, June 28, 2005 6:32 AM
                                    >To: spectrumanalyzer@yahoogroups.com
                                    >Subject: [spectrumanalyzer] UMS-2150 VCO versus ROS-2150VW
                                    >
                                    >Great work John, so much for that idea.
                                    >
                                    >Cash
                                    >
                                    ><?---- LSpots keywords ?><?---- HM ADS ?> <?---- LSpots keywords ?> <?----
                                    >HM ADS ?>
                                    >
                                    >----------
                                    >YAHOO! GROUPS LINKS
                                    >
                                    >  Visit your group
                                    > "< http://groups.yahoo.com/group/spectrumanalyzer >spectrumanalyzer" on the web.
                                    >
                                    >  To unsubscribe from this group, send an email to:
                                    >
                                    >< mailto:spectrumanalyzer-unsubscribe@yahoogroups.com?subject=Unsubscribe >spectrumanalyzer-unsubscribe@yahoogroups.com
                                    >
                                    >
                                    >  Your use of Yahoo! Groups is subject to the
                                    > < http://docs.yahoo.com/info/terms/>Yahoo! Terms of Service.
                                    >
                                    >----------

                                    <?---- LSpots keywords ?><?---- HM ADS ?> <?---- LSpots keywords ?> <?---- HM ADS ?>

                                    YAHOO! GROUPS LINKS

                                     Visit your group " spectrumanalyzer" on the web.
                                     To unsubscribe from this group, send an email to:
                                      spectrumanalyzer-unsubscribe@yahoogroups.com
                                     Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

                                  • william sprowls
                                    Hi all, Analog Devices AD8671 is also a good replacement for the OP27. I am using one in PLL 1 for the MSA. Its bias and noise specs are actually a little
                                    Message 17 of 20 , Jun 28, 2005
                                      Hi all,
                                      Analog Devices AD8671 is also a good replacement for
                                      the OP27. I am using one in PLL 1 for the MSA.
                                      Its bias and noise specs are actually a little better
                                      than the OP27. However, I see no better results than
                                      the OP27. This is due to the 20LogN noise of the PLL
                                      chip. It is the prevalent noise contribution in the
                                      system.
                                      It seems to be pretty hardy, too. I accidently
                                      crossed the +20v and -5v lines and it still works
                                      fine. Absolutely smoked the LMX 2326.
                                      Scotty

                                      --- "S. Cash Olsen" <KD5SSJ@...> wrote:

                                      > John,
                                      >
                                      > Well I didn't think to look and see what you were
                                      > using. The OP27 is
                                      > obsolete and is not or soon will not be readily
                                      > available. I'll make the
                                      > LT1677 a replacement part for the OP27.
                                      >
                                      > Thanks,
                                      >
                                      > Cash




                                      ____________________________________________________
                                      Yahoo! Sports
                                      Rekindle the Rivalries. Sign up for Fantasy Football
                                      http://football.fantasysports.yahoo.com
                                    Your message has been successfully submitted and would be delivered to recipients shortly.