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

[Richard Hosking]

There seems to be broad consensus about the mixer.
What about the LO for an HF board?
I presume it would have steps of about 50KHz, given the bandwidth of the 
audio board.
We could use a microwave PLL divided down

Richard

Philip Covington wrote:

>***** High Performance Software Defined Radio Discussion List *****
>
>  
>
>>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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