[A-DX] KIWI SDRs, v1.390: cross compilation, SAM demodulators

Sa Apr 25 12:45:18 CEST 2020


v1.390  April 23, 2020
     Performance improvements:
         Suggested by @howardsu on Kiwi forum: remove -DDEBUG so 
assert()'s are not evaluated.

     Added synchronous AM (SAM) demodulators from Warren Pratt's wdsp 
package via the
         Teensy-ConvolutionSDR implementation: 
         See the Kiwi operation manual for more information: 
         Synchronous AM modes: SAM, SAL, SAU, SAS


".....What is the "Synchronous AM" (SAM) demodulation mode?
As of software release v1.390 the Kiwi offers several versions of a 
synchronous AM detector for use with AM signals. The mode button toggles 
between a traditional double-sideband SAM detector and SAL and SAU which 
limit the passband to lower and upper sideband respectively. Use the 
keyboard shortcut 'A' to toggle the SAM modes.

Sideband selection overrides the Kiwi passband, i.e. if you are in SAL 
mode then adjusting the Kiwi LSB passband lower limit works as expected. 
But adjusting the Kiwi USB passband is totally ignored by the SAL 
demodulator because it is filtering out the upper sideband.

SAS offers a pseudo-stereo effect by routing SAL and SAU to the left and 
right ear exclusively. Note that SAS is a 2-channel mode like IQ so 
there is the same switching delay into and out of SAS as there is with 
IQ mode.


Das wäre dann " ionosphärisches Pseudo-Stereo"  wie beim  "ISB", bedingt 
durch unterschiedliche Phasenlage bei der separaten S-AM Demodulation 
von unterem und oberen Seitenband.