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Re: Si 570 programmers ? +/- 3500 ppm tuning

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  • w7qjq
    ... [snip] ... I have two Si570 s in the radio... one for Tx freq (direct 144 MHz) and one for Rx LO (4 x 10.7 MHz). The Rx one is solid for days. The Tx
    Message 1 of 13 , Apr 27, 2009
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      --- In softrock40@yahoogroups.com, "tigger" <aj-smith@...> wrote:
      >
      [snip]

      > But you do not say whether you have ever observed an automatic re-calibration or a 10ms dropout. I think the omission suggests you have not, though John (whom you quote) seems to assume that the recal happens (probably from reading the datasheet rather than from actual experience).

      I have two Si570's in the radio... one for Tx freq (direct 144 MHz) and one for Rx LO (4 x 10.7 MHz). The Rx one is solid for days. The Tx will intermittently reset, not when tuning it with the shortened tuning command but rather at odd times...maybe related to a power glitch(?).
      I have not noticed "a 10ms dropout".

      > Another point - in my system I re-establish the centre frequency by doing a full register write including freeze/unfreeze/new freq. I know that this produces a 250us glitch. In your 23320 message there is a suggestion that only N1/HSDIV/RFREQ/new-freq is required. Can you confirm that this is this the case ? If so, omitting freeze/unfreeze might reduce the glitch further. Can you comment on this ?
      >
      > Any G4OEP

      Yes, the shortened routine omits Freeze, UnFreeze, and Assert_New_Freq.

      73, Sid W7QJQ
      Oklahoma
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