[hpsdr] J/O testing

[FRANCIS CARCIA]

Hi All,
  Last night I decided to do some testing with my homebrew Tayloe front end at 455 KHz stand alone. My input is a 6 dB pad to set the input Z but I could still easily hear -130 dBM.
  My LO is a color burst crystal divided 8 so fairly clean. Then I increased the generator to saturation to see all the spurs generated. I got spurs at any frequency since the broadband input.  This made me wonder why nobody ever thought of active bandpass filters to limit the broad band crud from getting to the A/D? This would also help the broadband dynamic range. 
  The only problem I could see in doing this is matching the phase between I and Q channels.
  Anyone ever try this? 
  frank
   
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