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Date: Sun, 16 Jan 2005 22:30:00 +0100
From: Wolf DL4YHF <dl4yhf@freenet.de>
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Hi John,

Nice drawing, and much more complete than my "sketch" hi..

One question...
Was the L.O. using 74AC74 + 74AC08 better than the simple 74 HC 107 method ?

...and one suggestion:
To eliminate the need to adjust the offset voltage for the 4 input 
opamps, simply use AC-coupling. I found this very cute to reduce the 
number of trimpots to the minimum (namely zero). The TL084 which I used 
had an output offset error near 7 mV, the AC coupling (0.22 uF) between 
the OPAMP output and mixer input completely eliminates this. The 2.5 V 
bias for the switches was provided with a simple voltage divider from 
the 5 V supply.


So much for today, further experiments will follow soon.

Regards,
Wolf  DL4YHF .