The difference a simple QRQ CW transmit Bandpass filter can make on your RIG's TRANSMIT CW output QUALITY

the CW NOTE on the left is using a Raised cosine edge at 6ms rise/fall time with NO bandpass filtering...the harmonics are plentiful as shown on the spec an below it

the CW NOTE On the Right is using the same Raised cosine edge at 6ms - but in addition - is passing through a simple Gstreamer CLI bandpass filter...the BPF virtually eliminates all harmonics above and below the CW PITCH

Here is the command line Gstreamer CW BANDPASS FILTER code used   

CW PITCH = 680

gst-launch-1.0 jackaudiosrc ! queue ! "audio/x-raw,channels=1,rate=48000,format=F32LE" ! audioconvert ! audiowsincband mode=band-pass lower-frequency=580 upper-frequency=780 length=700 window=hamming ! audioconvert ! audioamplify amplification=1 ! audiorate ! queue ! jackaudiosink buffer-time=25000

NOTE:  the RIG is transmitting in AFCW Mode sending the CW AUDIO NOTE on the RIGHT to the RIG's LINE INPUT on LSB at a volume level below the threshold that would activate the RIG's internal ALC to turn on(NOTE: If the ALC gets would distort the cw rise time and the ALC action would cause unwanted harmonics to be transmitted along with the actual cw note)

Here is what the CW NOTE on the RIGHT sounds like:

Views: 79


You need to be a member of QRQcw to add comments!

Join QRQcw

© 2023   Created by Chuck aa0hw.   Powered by

Badges  |  Report an Issue  |  Terms of Service