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Re: Fw: Re: [softrock40] Rocky and SR-40

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  • Bill Dumke
    It is not a doubler. It just squares up the duty cycle to 50 %, if you are talking about the QRP2001 circuit. See:
    Message 1 of 11 , Dec 1, 2005
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      It is not a doubler. It just squares up the duty cycle to 50 %, if you
      are talking about the QRP2001 circuit. See:

      http://www.qrp2001.freeserve.co.uk/main.htm

      "U1, a quad XOR gate takes the Local Oscillator signal at twice the RF
      Input frequency. *U1a together with R2, R3 and C5 help to encourage a
      unity mark-space ratio on the signals going into U1b and U1c.* U1b is
      arranged as an inverter while U1c is just a buffer - hence the outputs
      from these devices are out of phase. These two signals are divided
      through flip-flops U2a and U2b, which are synchronised by U1d to force
      the required quadrature relationship. The flip-flop outputs directly
      drive the Tayloe bus switch select inputs."

      Bill

      Milt Cram wrote:

      > windy10605@... wrote:
      >
      >> OK !! it can be made to work OK. I notice the AD spec says 50% duty
      >> cycle +/-10% but I've never seen what it actually is across the
      >> frequency range. Some of the early info Alex published on Rocky shows
      >> a phase balance plot with around 12% and amplitude balance plot
      >> around 1.28. The typical comparator has both Q and Q(compliment)
      >> outputs so you probably don't need the XOR.
      >>
      >> 73 Kees K5BCQ
      >
      > Kees,
      >
      > I believe that the XOR is used as a frequency doubler. (If it has an
      > RC filter on one input--this causes an ouput pulse on both the rising
      > and falling edges of the input signal--i.e. at twice the frequency of
      > the input)
      >
      > Milt W8NUE
      >
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    • Milt Cram
      ... I stand corrected. Milt -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.362 / Virus Database: 267.13.10/189 - Release
      Message 2 of 11 , Dec 1, 2005
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        Bill Dumke wrote:

        >It is not a doubler. It just squares up the duty cycle to 50 %, if you
        >are talking about the QRP2001 circuit. See:
        >
        >
        I stand corrected.

        Milt


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      • Arthur J. Lekstutis
        Has anyone considered using a phase splitter like Rick Campbell KK7B shows in A Small High-Performance CW Transceiver Nov 1995 QST Vol 79 Number 11? (see
        Message 3 of 11 , Dec 2, 2005
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          Has anyone considered using a phase splitter like Rick Campbell KK7B
          shows in "A Small High-Performance CW Transceiver" Nov 1995 QST Vol 79
          Number 11? (see figure #2, L2). That fed into a pair of voltage
          comparators should be fairly broadband source for a digital QSD. I just
          ran it through spice and it looks like the phase difference could be
          fairly flat over much of the HF band, although it would certainly
          benefit from software calibration in-circuit (like Rocky does).

          Basically it's just a bridge with an inductor and capacitor in each leg,
          with the inductors coupled (i.e. a transformer). Each capacitor connects
          to both inductors, and each inductor connects to both capacitors.

          Later,
          Artie Lekstutis
          KC2MFS

          >I want to run a couple more test and make sure I'm not missing
          >something major in my simulation and then I'll post it.
          >
          >Basically, the comparators compare the signal differentially( looking
          >for zero crossing) and are fed the signals through a isolating
          >transformer, one comparator receives the oscillator signal divided by
          >two (in amplitude), the other, is fed by another isolated secondary
          >and is fed through a slightly modified RC network(multiple poles) and
          >again compared in differential mode (detecting the zero-crossing).
          >Because the signal is +- to ground I need a -Vcc on the
          >comparator, but there are ways to get around that also, I could
          >reference the whole thing to 1/2 the Vcc.
          >
          >The goal is to have the filter have a delay that is linearly related
          >to it's frequency, so as the frequency goes up the delay decreases by
          >the ratio of the frequency, in that way they stay in Quadrature.
          >
          >As the frequency changes the two signals stay in quadrature but the
          >second signal decreases in amplitude( which doesn't matter since I'm
          >looking at the zero crossing), eventually the second signal is too
          >low to reliably detect it's zero crossing, but by then we are way up
          >in frequency.
          >
          >Looks great on the PC screen, but it might not play out in reality,
          >but it might work over a much wider range, which would be handy if
          >using a DDS to move around a range of frequencies.
          >
          >What Spice doesn't tell me without having a more detailed simulation
          >is how much jitter there is at the higher frequencies, but I would be
          >happy if it could do a 2:1 ratio of frequencies, on Spice it looks
          >like it will do 8:1 ratio
          >
          >There are additional components, a hexfiliar transformer, a couple of
          >extra R's and C's, and it's wired a little different, and the signal
          >source must be a sine wave. My main problem right now is a lack of a
          >DDS that is functional, but a FT-817 with a attenuator will do for
          >test in the ham bands only. Also a lack of a SR-5 but that will be
          >remedied soon I hope.
          >
          >Warning this idea has been copyrighted, any attempt to steal it
          >without giving due credit will be met by the use of nuclear weapons.
          >
          >Details later if it works out, same Bat Time, same Bat Channel.
          >
          >
          >At 01:22 PM 12/1/2005, you wrote:
          >
          >
          >>Interesting ! Care to give us some more detail ?
          >>
          >>73 Kees K5BCQ
          >>
          >>
          >>softrock40" on the web.
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          >>
          >>----------
          >>
          >>
          >
          >
          >Cecil Bayona
          >KD5NWA
          >www.qrpradio.com
          >
          >I fail to see why doing the same thing over and over and getting the
          >same results every time is insanity: I've almost proved it isn't;
          >only a few more tests now and I'm sure results will differ this time ...
          >
          >
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        • Arthur J. Lekstutis
          Hi, I m not an analog guy, and I am new to ham radio, so maybe I have this all wrong. I was trying to ask for the opinions of others on this subject. It looks
          Message 4 of 11 , Dec 2, 2005
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            Hi,

            I'm not an analog guy, and I am new to ham radio, so maybe I have this
            all wrong. I was trying to ask for the opinions of others on this subject.

            It looks to me like a variation of the circuit that Rick Campbell KK7B
            used is a fairly wide band solution of deriving a pair of signals with
            one having a 90 degree phase offset from the other. I expect the output
            to be connected to a pair of voltage comparators to feed the video switch.
            http://Lekstutis.com/Artie/Ham/Images/PhaseSplitter_002.GIF

            The circuit loss is not insignificant at 17db max, but that does seem
            workable.

            Can this work, or am I missing something?

            Thanks!

            Later,
            Artie Lekstutis
            KC2MFS

            >Has anyone considered using a phase splitter like Rick Campbell KK7B
            >shows in "A Small High-Performance CW Transceiver" Nov 1995 QST Vol 79
            >Number 11? (see figure #2, L2). That fed into a pair of voltage
            >comparators should be fairly broadband source for a digital QSD. I just
            >ran it through spice and it looks like the phase difference could be
            >fairly flat over much of the HF band, although it would certainly
            >benefit from software calibration in-circuit (like Rocky does).
            >
            >Basically it's just a bridge with an inductor and capacitor in each leg,
            >with the inductors coupled (i.e. a transformer). Each capacitor connects
            >to both inductors, and each inductor connects to both capacitors.
            >
            >Later,
            >Artie Lekstutis
            >KC2MFS
            >
            >
            >
          • Bill Dumke
            Arthur, All that is, is what RF and microwave engineers call a quadrature hybrid. Normally you use 50 Ohms at all ports. I don t know why he chose the
            Message 5 of 11 , Dec 2, 2005
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              Arthur,

              All that is, is what RF and microwave engineers call a quadrature
              hybrid. Normally you use 50 Ohms at all ports. I don't know why he
              chose the resistor values the way he did, maybe he was trying to
              minimize the loss. Sure you can get 90 degrees phase shift, but it
              will still be band linmited.

              The advantage of the digital scheme is that the continuous frequency
              coverage for 90 degrees will be a lot better. But that can certainly be
              band limited as well. It will, however work, everywhere below some
              frequency. Whereas the quadrature hybrid will be limited to some
              bandpass for a specific accuracy.

              Bill WB5TCO

              Arthur J. Lekstutis wrote:

              > Hi,
              >
              > I'm not an analog guy, and I am new to ham radio, so maybe I have this
              > all wrong. I was trying to ask for the opinions of others on this subject.
              >
              > It looks to me like a variation of the circuit that Rick Campbell KK7B
              > used is a fairly wide band solution of deriving a pair of signals with
              > one having a 90 degree phase offset from the other. I expect the output
              > to be connected to a pair of voltage comparators to feed the video switch.
              > http://Lekstutis.com/Artie/Ham/Images/PhaseSplitter_002.GIF
              >
              > The circuit loss is not insignificant at 17db max, but that does seem
              > workable.
              >
              > Can this work, or am I missing something?
              >
              > Thanks!
              >
              > Later,
              > Artie Lekstutis
              > KC2MFS
              >
              > >Has anyone considered using a phase splitter like Rick Campbell KK7B
              > >shows in "A Small High-Performance CW Transceiver" Nov 1995 QST Vol 79
              > >Number 11? (see figure #2, L2). That fed into a pair of voltage
              > >comparators should be fairly broadband source for a digital QSD. I just
              > >ran it through spice and it looks like the phase difference could be
              > >fairly flat over much of the HF band, although it would certainly
              > >benefit from software calibration in-circuit (like Rocky does).
              > >
              > >Basically it's just a bridge with an inductor and capacitor in each leg,
              > >with the inductors coupled (i.e. a transformer). Each capacitor connects
              > >to both inductors, and each inductor connects to both capacitors.
              > >
              > >Later,
              > >Artie Lekstutis
              > >KC2MFS
              > >
              > >
              > >
              >
              >
              >
              >
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              > Shortwave receivers
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              > <http://groups.yahoo.com/group/softrock40>" on the web.
              >
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            • Arthur J. Lekstutis
              Bill, Rick Cambpell KK7B used 50 Ohms on all ports in his design (http://www.arrl.org/members-only/tis/info/pdf/9511041.pdf). I see now that I had
              Message 6 of 11 , Dec 3, 2005
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                Bill,

                Rick Cambpell KK7B used 50 Ohms on all ports in his design
                (http://www.arrl.org/members-only/tis/info/pdf/9511041.pdf). I see now
                that I had mis-calculated his inductors (he published only number of
                turns and core type). Running his values I see that it has similar
                performance to my values, but the impedances are all 50 ohms. The
                bandwidth is limited, but over the ham hf bands it has a fairly flat
                phase difference, and the loss is no worse than 17db. Considering that
                the output is going to a voltage comparator, the 17db might not be too
                bad and would give a full decade of bandwidth. Perhaps phase noise would
                increase at the extremes?
                http://Lekstutis.com/Artie/Ham/Images/PhaseSplitter_001.GIF

                I prefer the all digital schemes for my own experimentation, but they
                require a 2x or higher clock. There are certainly cases where analog
                designs have their advantage though, and the SoftRock v5.0 is a clear
                example (putting an RC phase shifter on the band module). There may be
                other cases where an all hf bands phase splitter may be desirable, and I
                was just trying to point out one candidate I knew of and ask if it would
                be usable to those that are interested.

                Can't wait to get my SoftRock v5.0 :-)

                Later,
                Artie Lekstutis
                KC2MFS

                >Arthur,
                >
                >All that is, is what RF and microwave engineers call a quadrature
                >hybrid. Normally you use 50 Ohms at all ports. I don't know why he
                >chose the resistor values the way he did, maybe he was trying to
                >minimize the loss. Sure you can get 90 degrees phase shift, but it
                >will still be band linmited.
                >
                >The advantage of the digital scheme is that the continuous frequency
                >coverage for 90 degrees will be a lot better. But that can certainly be
                >band limited as well. It will, however work, everywhere below some
                >frequency. Whereas the quadrature hybrid will be limited to some
                >bandpass for a specific accuracy.
                >
                >Bill WB5TCO
                >
                >Arthur J. Lekstutis wrote:
                >
                >
                >
                >>Hi,
                >>
                >>I'm not an analog guy, and I am new to ham radio, so maybe I have this
                >>all wrong. I was trying to ask for the opinions of others on this subject.
                >>
                >>It looks to me like a variation of the circuit that Rick Campbell KK7B
                >>used is a fairly wide band solution of deriving a pair of signals with
                >>one having a 90 degree phase offset from the other. I expect the output
                >>to be connected to a pair of voltage comparators to feed the video switch.
                >> http://Lekstutis.com/Artie/Ham/Images/PhaseSplitter_002.GIF
                >>
                >>The circuit loss is not insignificant at 17db max, but that does seem
                >>workable.
                >>
                >>Can this work, or am I missing something?
                >>
                >>Thanks!
                >>
                >>Later,
                >>Artie Lekstutis
                >>KC2MFS
                >>
                >>
                >>
                >>>Has anyone considered using a phase splitter like Rick Campbell KK7B
                >>>shows in "A Small High-Performance CW Transceiver" Nov 1995 QST Vol 79
                >>>Number 11? (see figure #2, L2). That fed into a pair of voltage
                >>>comparators should be fairly broadband source for a digital QSD. I just
                >>>ran it through spice and it looks like the phase difference could be
                >>>fairly flat over much of the HF band, although it would certainly
                >>>benefit from software calibration in-circuit (like Rocky does).
                >>>
                >>>Basically it's just a bridge with an inductor and capacitor in each leg,
                >>>with the inductors coupled (i.e. a transformer). Each capacitor connects
                >>>to both inductors, and each inductor connects to both capacitors.
                >>>
                >>>Later,
                >>>Artie Lekstutis
                >>>KC2MFS
                >>>
                >>>
                >>>
              • KD5NWA
                I ve been trying among other things using a RC bridge to see if the Quadrature will stay in phase for a longer range of frequencies. One side a High-Pass
                Message 7 of 11 , Dec 3, 2005
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                  I've been trying among other things using a RC bridge to see if the
                  Quadrature will stay in phase for a longer range of frequencies. One
                  side a High-Pass filter, the other a low pass, it's been working very
                  well on Spice over 4.5 Octaves of frequency. I will have to try this
                  one using inductors and see if the losses are less than the RC variety.

                  In all these experiments I use a comparator to detect the zero
                  crossing of signals since the amplitudes are not constant, also many
                  DDS cards do not have a constant amplitude as you change frequencies.

                  By using zero crossing detection you also eliminate changes if your
                  power supply changes or the clock input amplitude changes.

                  In my original experiment I detected the zero crossing of the clock
                  as one phase, and the same clock through a constant phase RC network.
                  As the frequency of the Clock changes the second signal has a
                  changing delay keeping that signal in Quadrature to the clock. The
                  amplitude of the second signal keeps decreasing as you go higher in
                  frequency, so the only reliable detection is the zero crossing, that
                  seem to work over several octaves.

                  Right now I have been using SPICE to do simulations, but I am in the
                  process of buying parts to actually build these circuits.

                  If having fun is illegal , I would be in a lot of trouble!

                  Thanks for bring the LC bridge to my attention.

                  At 09:22 AM 12/3/2005, you wrote:
                  >Bill,
                  >
                  >Rick Cambpell KK7B used 50 Ohms on all ports in his design
                  >(http://www.arrl.org/members-only/tis/info/pdf/9511041.pdf). I see now
                  >that I had mis-calculated his inductors (he published only number of
                  >turns and core type). Running his values I see that it has similar
                  >performance to my values, but the impedances are all 50 ohms. The
                  >bandwidth is limited, but over the ham hf bands it has a fairly flat
                  >phase difference, and the loss is no worse than 17db. Considering that
                  >the output is going to a voltage comparator, the 17db might not be too
                  >bad and would give a full decade of bandwidth. Perhaps phase noise would
                  >increase at the extremes?
                  > http://Lekstutis.com/Artie/Ham/Images/PhaseSplitter_001.GIF
                  >
                  >I prefer the all digital schemes for my own experimentation, but they
                  >require a 2x or higher clock. There are certainly cases where analog
                  >designs have their advantage though, and the SoftRock v5.0 is a clear
                  >example (putting an RC phase shifter on the band module). There may be
                  >other cases where an all hf bands phase splitter may be desirable, and I
                  >was just trying to point out one candidate I knew of and ask if it would
                  >be usable to those that are interested.
                  >
                  >Can't wait to get my SoftRock v5.0 :-)
                  >
                  >Later,
                  >Artie Lekstutis
                  >KC2MFS
                  >
                  > >Arthur,
                  > >
                  > >All that is, is what RF and microwave engineers call a quadrature
                  > >hybrid. Normally you use 50 Ohms at all ports. I don't know why he
                  > >chose the resistor values the way he did, maybe he was trying to
                  > >minimize the loss. Sure you can get 90 degrees phase shift, but it
                  > >will still be band linmited.
                  > >
                  > >The advantage of the digital scheme is that the continuous frequency
                  > >coverage for 90 degrees will be a lot better. But that can certainly be
                  > >band limited as well. It will, however work, everywhere below some
                  > >frequency. Whereas the quadrature hybrid will be limited to some
                  > >bandpass for a specific accuracy.
                  > >
                  > >Bill WB5TCO
                  > >
                  > >Arthur J. Lekstutis wrote:
                  > >
                  > >
                  > >
                  > >>Hi,
                  > >>
                  > >>I'm not an analog guy, and I am new to ham radio, so maybe I have this
                  > >>all wrong. I was trying to ask for the opinions of others on this subject.
                  > >>
                  > >>It looks to me like a variation of the circuit that Rick Campbell KK7B
                  > >>used is a fairly wide band solution of deriving a pair of signals with
                  > >>one having a 90 degree phase offset from the other. I expect the output
                  > >>to be connected to a pair of voltage comparators to feed the video switch.
                  > >> http://Lekstutis.com/Artie/Ham/Images/PhaseSplitter_002.GIF
                  > >>
                  > >>The circuit loss is not insignificant at 17db max, but that does seem
                  > >>workable.
                  > >>
                  > >>Can this work, or am I missing something?
                  > >>
                  > >>Thanks!
                  > >>
                  > >>Later,
                  > >>Artie Lekstutis
                  > >>KC2MFS
                  > >>
                  > >>
                  > >>
                  > >>>Has anyone considered using a phase splitter like Rick Campbell KK7B
                  > >>>shows in "A Small High-Performance CW Transceiver" Nov 1995 QST Vol 79
                  > >>>Number 11? (see figure #2, L2). That fed into a pair of voltage
                  > >>>comparators should be fairly broadband source for a digital QSD. I just
                  > >>>ran it through spice and it looks like the phase difference could be
                  > >>>fairly flat over much of the HF band, although it would certainly
                  > >>>benefit from software calibration in-circuit (like Rocky does).
                  > >>>
                  > >>>Basically it's just a bridge with an inductor and capacitor in each leg,
                  > >>>with the inductors coupled (i.e. a transformer). Each capacitor connects
                  > >>>to both inductors, and each inductor connects to both capacitors.
                  > >>>
                  > >>>Later,
                  > >>>Artie Lekstutis
                  > >>>KC2MFS
                  > >>>
                  > >>>
                  > >>>
                  >
                  >
                  >
                  >
                  >
                  >
                  >Yahoo! Groups Links
                  >
                  >
                  >
                  >


                  Cecil Bayona
                  KD5NWA
                  www.qrpradio.com

                  "I fail to see why doing the same thing over and over and getting the
                  same results every time is insanity: I've almost proved it isn't;
                  only a few more tests now and I'm sure results will differ this time ... "
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