On 27/11/2010 02:58, Vitaliy wrote:
> John Coppens wrote:
>>>> I've never seen FSK at 9k6, but if it really has to be that, and it ha=
s
>>>> to be baseband, I guess the old VCO/PLL pair could do the job (2 ICs
>>>> though, _and_ analog) IIRC XR2206 and XR2211 or so.
>>> This may be exactly what I was looking for... reading the datasheets no=
w,
>>> thanks!
>> You're welcome... You might be helped with some other ICs from that
>> era, like the NE565 (or LM565), and some even used the CD4046 to decode
>> FSK. And don't discard using an FM chip to decode FSK. I once used the
>> TDA120 to do that for data and Fax signals (analog fax).
> I decided to read read up on the theory in Miller's "Modern Electronic
> Communication", and guess what I found... a circuit of a Full-duplex mode=
m
> based on the XR-2206 and XR-2211. :-)
>
> Vitaliy
>
I like happy endings.
I've also seen RTTY decoder done with a pair of NE567s
FM receiver ICs, can work, but some might have internal small C and thus=20
have a minimum frequency. I've used a low noise cascode amp that is=20
100MHz to 4GHz with lower limit due to internal capacitor.
--=20
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