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Quadrature DDS device?

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  • efkrome
    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
    Message 1 of 14 , Nov 1, 2007
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      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
    • Art
      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
      Message 2 of 14 , Nov 1, 2007
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        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,

        Ar
        t


        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?
      • 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 3 of 14 , Nov 1, 2007
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          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 4 of 14 , Nov 1, 2007
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            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 5 of 14 , Nov 1, 2007
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              ----- 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 6 of 14 , Nov 1, 2007
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                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 7 of 14 , Nov 1, 2007
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                  --- 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 8 of 14 , Nov 1, 2007
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                    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 9 of 14 , Nov 1, 2007
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                      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 10 of 14 , Nov 1, 2007
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                        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 11 of 14 , Nov 2, 2007
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                          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 12 of 14 , Nov 2, 2007
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                            --- 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 13 of 14 , Nov 2, 2007
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                              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 14 of 14 , Nov 2, 2007
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                                > 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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