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Re: FT1000 MK5 Field / Icom radio IF panadapter.

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  • Giancarlo
    Hi Marco, pse see below ... comparator ... OK. Going lower in frequency you will have a lower effect of group delay. ... this ... Nothing is perfect in this
    Message 1 of 9 , Jun 2, 2006
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      Hi Marco,

      pse see below

      --- In softrock40@yahoogroups.com, "ccmarco2004" <ccmarco@...> wrote:
      >
      > Hi Gian,
      >
      > many thanks for detailed FT-1000 IF connection aid.
      >
      > I have just a question about v7.0 schematic :
      >
      > yesterday i was simulating the shifter network for 10 meter band
      > version (R8: 1K, C9 : 10pF), and taking into account the
      comparator
      > propagation delay, 4.2 nS, and input capacitance, 2 pF, i have
      > obtained a total group delay greater than expected (8.86 nS, 90
      > degree @ 28.204 MHz).

      OK. Going lower in frequency you will have a lower effect of group
      delay.

      > I also thinked that could be very difficult trim & fix exactly
      this
      > delay, due to parassitic parameter variance (thermal, aging, etc
      > etc).

      Nothing is perfect in this world ... so you have to compromise ...
      and adapt yourself and the circuit...hi

      > From this aspect, is not much better the v6.0 configuration, with
      > digital divider ?

      Yes

      > Am i wrong in some way ?

      NO

      > Could you quickly explain me performance differences from SR v6.0
      > and v7.0 ?

      I havent done any measurements comparison between the two. The V6
      certainly has a better quadrature generation.

      I am working an a digital quadrature circuit where we have a divide
      by 2 that will make possible to reduce the L.O. frequency
      particularly going up to 28-30MHz band.

      I will keep the group posted ... last night I got a fault on the
      OPA ...one channel went bang !"!! hi

      Going out for lunch with XYL, family and friend to celebrate out
      37th wedding anniversary ...hi

      73

      Gian
      I7SWX
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