Re: [amsat-bb] DownConverter Fromula needed!!

[Chris Hill <crh_telnet@xxxxxxxxxxx>]

Hi Nick,

The IF multiplication chain of x3 then x 2 doesn't make sense to me.

However, here's an educated guess as to the formula you need:

1.  Generic
===========
OUT = IN - 12 x LO


2.  144MHz IF, using 96MHz crystal for LO
========================================
OUT = IN - 12 x 96
    = IN - 1152

eg   1296.8MHz will appear as a non-inverted signal at 144.8MHz


3.  28MHz IF, using 105.66MHz crystal for LO
========================================
OUT = IN - 12 x 96
    = IN - 1267.92

eg   1296.8MHz will appear as a non-inverted signal at 28.88MHz



Note:  By "non-inverted signal", I mean that an USB signal on 1.2GHz will
be presented as an USB signal at the IF of 28MHz or 144MHz.

I hope this is of some use to you.


73 Chris vk6kch






At 11:33 1999/12/22 +0200, you wrote:
> Hi,
>O.k. Sorry! This time I will be more accurate. The DownConverter is
"homemade".
>To help you, below I write the characteristics of the components so you
>could give
>me some more "accurate" results:
>
>RF-Input: 1296,8 Mhz
>IF-Output: 28-30 Mhz or 144-146 Mhz
>Crystal Oscillator: 96/105.66 Mhz
>
>And some more info:
>It contains two multipliers one x3 (288/317 Mhz) and one x2 (576/634 Mhz)
>
>I think now I think I gave you enough info!!!
>
>Thanks again for the replys!
>------------------------
>Kavalieris Nick, SV1ETK,
>phantome@mail.ru
>
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>

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