[hpsdr] Proposal for a 'low-end' RX/TX board for HPSDR

[Philip Covington]

> Hi Ray, Phil_C, Phil_H, Bob, et al,
>
> Bob's idea of a potential QSD (July 07, 2006) with fast analog
> switches is very interesting. There might be a small error, though.
> Pin 2 of U5 obviously should go to Pin 1 of U2?
> <svn://206.216.146.154/svn/repos_sdr_hpsdr/trunk/N4HY/Horton/QSD.pdf>.
>
> Using those components I figured out another configuration. Instead of
> using 90° narrow sampling pulses, I plan to use 180° wide pulses in
> quadrature. Transformer coupled dual line receivers split the I and Q
> signals from the DDS to pair of opposite pulses with minimal skew and
> timing errors.
>
> See this and tell me what I possibly missed:
> <http://kotisivu.dnainternet.net/ahti/sdr-1000/newmix2.pdf>
>
> Ahti OH2RZ

Hi Ahti,

Here is another one to look at:

<http://www.philcovington.com/HPSDR/TEMP_STUFF/isd_07262006-1.pdf>

I went slightly different and used a SN74AUC2G53.

73 de Phil N8VB

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