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Re: [softrock40] Quadrature DDS device?

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  • FRANCIS CARCIA
    yes, this is the DDS in SDR1000 but it makes a lot of spurs on 20m. efkrome wrote: Re: discussions about various DDS chips and
    Message 1 of 14 , Nov 1, 2007
      yes, this is the DDS in SDR1000 but it makes a lot of spurs on 20m.

      efkrome <efkrome@...> wrote:
      Re: discussions about various DDS chips and some adventerous souls (my
      hat is off to you!)in process of designing boards to use them. Since
      this forum is all about Softrock, wouldn't it make sense to have a DDS
      based on one of the chips that have built-in quadrature output, such
      as AD9854 or AD9958? I'm not a DDS person, but wouldn't such
      quadrature output be suitable for driving the commutating detector
      directly, without phase-shifting flip-flop arrangement? Or am I
      missing something? Thanks!

      Ed K9EK
      EM69xd


    • Thomas
      Hello, what is about a combination of a DDS from Analog Devices and a PLL. -- Could the DDS be used as a reference oscillator of the PLL and the PLL for
      Message 2 of 14 , Nov 1, 2007
        Hello,
        what is about a combination of a DDS from Analog Devices and a PLL.

        -- Could the DDS be used as a reference oscillator of the PLL and the
        PLL for clean-up of the signal?

        I have not seen ham circuits showing this combination so far but I
        think it could use the advantages of a DDS and a PLL.

        Thank You!
        Thomas, DF7TV

        --- In softrock40@yahoogroups.com, FRANCIS CARCIA <carcia@...> wrote:
        >
        > yes, this is the DDS in SDR1000 but it makes a lot of spurs on 20m.
        >
        > efkrome <efkrome@...> wrote: Re: discussions about various
        DDS chips and some adventerous souls (my
        > hat is off to you!)in process of designing boards to use them. Since
        > this forum is all about Softrock, wouldn't it make sense to have a DDS
        > based on one of the chips that have built-in quadrature output, such
        > as AD9854 or AD9958? I'm not a DDS person, but wouldn't such
        > quadrature output be suitable for driving the commutating detector
        > directly, without phase-shifting flip-flop arrangement? Or am I
        > missing something? Thanks!
        >
        > Ed K9EK
        > EM69xd
        >
      • Leon
        ... From: Thomas To: Sent: Thursday, November 01, 2007 4:09 PM Subject: [softrock40] Re: Quadrature
        Message 3 of 14 , Nov 1, 2007
          ----- Original Message -----
          From: "Thomas" <softdescartes@...>
          To: <softrock40@yahoogroups.com>
          Sent: Thursday, November 01, 2007 4:09 PM
          Subject: [softrock40] Re: Quadrature DDS device?


          > Hello,
          > what is about a combination of a DDS from Analog Devices and a PLL.
          >
          > -- Could the DDS be used as a reference oscillator of the PLL and the
          > PLL for clean-up of the signal?
          >
          > I have not seen ham circuits showing this combination so far but I
          > think it could use the advantages of a DDS and a PLL.

          They have been used, but are not very popular for homebrewed rigs because of
          their complexity. Yaesu FT-817D and FT-757 transceivers use that technique,
          other manufacturers probably use it also.

          73, Leon
          --
          Leon Heller
          Amateur radio call-sign G1HSM
          Yaesu FT-817ND and FT-857D transceivers
          Suzuki SV1000S motorcycle
          leon355@...
          http://www.geocities.com/leon_heller
        • brainerd@wildblue.net
          ... KE5FX published an article on just such a PLL/DDS for 1 to 2 GHZ in an issue of QEX 2 or 3 years ago I think. Dave - WB6DHW
          Message 4 of 14 , Nov 1, 2007
            On 1 Nov 2007 at 16:18, Leon wrote:

            > ----- Original Message -----
            > From: "Thomas" <softdescartes@...>
            > To: <softrock40@yahoogroups.com>
            > Sent: Thursday, November 01, 2007 4:09 PM
            > Subject: [softrock40] Re: Quadrature DDS device?
            >
            >
            > > Hello,
            > > what is about a combination of a DDS from Analog Devices and a PLL.
            > >
            > > -- Could the DDS be used as a reference oscillator of the PLL and the
            > > PLL for clean-up of the signal?
            > >
            > > I have not seen ham circuits showing this combination so far but I
            > > think it could use the advantages of a DDS and a PLL.
            >
            KE5FX published an article on just such a PLL/DDS for 1 to 2 GHZ in an
            issue of QEX 2 or 3 years ago I think.

            Dave - WB6DHW
            <http://wb6dhw>
          • Giancarlo
            ... features ... have a DDS ... such ... Yes, there shouold be a very performing possibility of a quadrature DDS using two AD9910 (99ten) covering at least to
            Message 5 of 14 , Nov 1, 2007
              --- In softrock40@yahoogroups.com, Art <KY1K@...> wrote:
              >
              > Ed, you're right of course!
              >
              > But, generally people who want 4 outputs usually want other
              features
              > and want extremely good spectral purity. The 98x series isn't known
              > for that, but hopefully they will build a chip with quadrature
              > outputs when they finally figure out how to make the output clean.
              >
              > I'd love to see a quadrature output 9912 chip!
              >
              > Regards,
              >
              > Art
              >
              >
              > >Since this forum is all about Softrock, wouldn't it make sense to
              have a DDS
              > >based on one of the chips that have built-in quadrature output,
              such
              > >as AD9854 or AD9958?
              >

              Yes, there shouold be a very performing possibility of a quadrature
              DDS using two AD9910 (99ten) covering at least to VHF maybe up to
              400MHz.

              73

              Gian
              I7SWX
            • Jason Hitesman
              ... With the article about his Star-10 in the current QEX I ve been doing some reading on KW7CD, Cornell Drentea s website:
              Message 6 of 14 , Nov 1, 2007
                On Nov 1, 2007 9:09 AM, Thomas <softdescartes@...> wrote:

                > -- Could the DDS be used as a reference oscillator of the PLL and the
                > PLL for clean-up of the signal?
                >
                > I have not seen ham circuits showing this combination so far but I
                > think it could use the advantages of a DDS and a PLL.

                With the article about his Star-10 in the current QEX I've been doing
                some reading on KW7CD, Cornell Drentea's website:
                http://members.aol.com/cdrentea/myhomepage/

                Quite a bit of what he has available on his site has to do with
                DDS-driven PLL's. I've been meaning to find time to read most of it
                for over a year...and the QEX article has got me finally making time
                for some of it.

                ----
                Jason Hitesman
                N8INJ
              • Ramakrishnan Muthukrishnan
                ... Hi Thomas, Apart from the article by John Miles KE5FX, there was a wonderful QEX article (which incidentally I am reading currently and am planning to
                Message 7 of 14 , Nov 1, 2007
                  On 11/1/07, Thomas <softdescartes@...> wrote:
                  > Hello,
                  > what is about a combination of a DDS from Analog Devices and a PLL.
                  >
                  > -- Could the DDS be used as a reference oscillator of the PLL and the
                  > PLL for clean-up of the signal?
                  >
                  > I have not seen ham circuits showing this combination so far but I
                  > think it could use the advantages of a DDS and a PLL.

                  Hi Thomas,

                  Apart from the article by John Miles KE5FX, there was a wonderful QEX
                  article (which incidentally I am reading currently and am planning to
                  homebrew) by Steve Hageman on a 2-250Mhz Signal source. It is has an
                  adjustable level based on an PIN diode attenuator and an ALC loop. The
                  article appeared sometime in 2000. Don't have the article with me
                  right now to tell you the exact month. The PCBs are available from FAR
                  Circuits.

                  73
                  Ramakrishnan VU3RDD
                • Thomas
                  Hello Ramakrishnan, Many thanks for the information. Well several years ago I read some articles of Steve Hageman but not this one. For the group I think I
                  Message 8 of 14 , Nov 1, 2007
                    Hello Ramakrishnan,
                    Many thanks for the information.
                    Well several years ago I read some articles of Steve Hageman but
                    not this one.

                    For the group I think I found the project you mention at his new homepage:

                    http://www.analoghome.com/projects/dds_pll.html

                    Please let us know how your building ends.

                    Namashte, 73
                    Thomas, DF7TV

                    --- In softrock40@yahoogroups.com, "Ramakrishnan Muthukrishnan"
                    <vu3rdd@...> wrote:
                    >
                    > On 11/1/07, Thomas <softdescartes@...> wrote:
                    > > Hello,
                    > > what is about a combination of a DDS from Analog Devices and a PLL.
                    > >
                    > > -- Could the DDS be used as a reference oscillator of the PLL and the
                    > > PLL for clean-up of the signal?
                    > >
                    > > I have not seen ham circuits showing this combination so far but I
                    > > think it could use the advantages of a DDS and a PLL.
                    >
                    > Hi Thomas,
                    >
                    > Apart from the article by John Miles KE5FX, there was a wonderful QEX
                    > article (which incidentally I am reading currently and am planning to
                    > homebrew) by Steve Hageman on a 2-250Mhz Signal source. It is has an
                    > adjustable level based on an PIN diode attenuator and an ALC loop. The
                    > article appeared sometime in 2000. Don't have the article with me
                    > right now to tell you the exact month. The PCBs are available from FAR
                    > Circuits.
                    >
                    > 73
                    > Ramakrishnan VU3RDD
                    >
                  • Thomas
                    Here is a further link to the more ham related pages of Steve Hageman: http://www.geocities.com/hagtronics/source/index.html 73 Thomas, DF7TV
                    Message 9 of 14 , Nov 2, 2007
                      Here is a further link to the more ham related pages of
                      Steve Hageman:

                      http://www.geocities.com/hagtronics/source/index.html


                      73
                      Thomas, DF7TV

                      --- In softrock40@yahoogroups.com, "Thomas" <softdescartes@...> wrote:
                      >
                      > Hello Ramakrishnan,
                      > Many thanks for the information.
                      > Well several years ago I read some articles of Steve Hageman but
                      > not this one.
                      >
                      > For the group I think I found the project you mention at his new
                      homepage:
                      >
                      > http://www.analoghome.com/projects/dds_pll.html
                      >
                      > Please let us know how your building ends.
                      >
                      > Namashte, 73
                      > Thomas, DF7TV
                      >
                    • aaintil
                      ... Ramakrishnan, Hageman s article is in January/February 2000 QEX, but I think the components used are more or less obsolete. The article of John Miles and
                      Message 10 of 14 , Nov 2, 2007
                        --- In softrock40@yahoogroups.com, "Ramakrishnan Muthukrishnan"
                        <vu3rdd@...> wrote:
                        >> Apart from the article by John Miles KE5FX, there was a wonderful QEX
                        > article (which incidentally I am reading currently and am planning to
                        > homebrew) by Steve Hageman on a 2-250Mhz Signal source. >

                        Ramakrishnan,

                        Hageman's article is in January/February 2000 QEX, but I think the
                        components used are more or less obsolete. The article of John Miles
                        and Richard Hosking is in March/April 2004.

                        73, Ahti OH2RZ
                      • Ramakrishnan Muthukrishnan
                        ... Ahti, Thanks. It looks like Steve maintains a page with the component details. I am yet to see a benchtop signal source project (other than of course
                        Message 11 of 14 , Nov 2, 2007
                          On 11/2/07, aaintil <aaintil@...> wrote:
                          >
                          > Ramakrishnan,
                          >
                          > Hageman's article is in January/February 2000 QEX, but I think the
                          > components used are more or less obsolete. The article of John Miles
                          > and Richard Hosking is in March/April 2004.
                          >
                          > 73, Ahti OH2RZ

                          Ahti,

                          Thanks. It looks like Steve maintains a page with the component details.

                          I am yet to see a benchtop signal source project (other than of course
                          Hageman's) which has adjustable level together with the usual
                          frequency. May be we should have a new homebrew project to have a nice
                          quality benchtop generator with an adjustable level/frequency
                          adjustment.

                          Ramakrishnan VU3RDD
                        • brainerd@wildblue.net
                          ... My 995x board has a programmable 0 - 31.5 dB attenuater on the output. Although the board was designed to be controlled by a PC through the USB port, the
                          Message 12 of 14 , Nov 2, 2007
                            > I am yet to see a benchtop signal source project (other than of course
                            > Hageman's) which has adjustable level together with the usual
                            > frequency. May be we should have a new homebrew project to have a nice
                            > quality benchtop generator with an adjustable level/frequency
                            > adjustment.
                            >
                            > Ramakrishnan VU3RDD
                            >
                            My 995x board has a programmable 0 - 31.5 dB attenuater on the output. Although the
                            board was designed to be controlled by a PC through the USB port, the on-board PIC could
                            be programmed to make a stand alone unit.

                            Dave - WB6DHW
                            <http://wb6dhw.com>
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