High-pass filter on IQ demodulator live audio out
Hi everyone,
SDRDharp author (@lambdaprog) recently included a new AM splatter and co-channel QRM canceller. I've got some really cool results using KiwiSDR IQ demodulator, saving the recording to a WAV file and opening it on SDR#.
Next, I tried routing the KiwiSDR live audio out to SDRSharp (used Virtual Audio Cable). But I've got something unexpected for a IQ stream. It seems there a high-pass filter in effect notching the range around 0 to 70Hz on both left and right channels This effectively kills the AM carrier required by the canceller algorithm.
I found Firefox may pass audio thru an HPF under certain codecs. VAC has a Channel Mixing option. I toggled off both neither removed the HPF.
I also tried visualizing the live IQ out on Audacity and, sure enough, the lower 60-70Hz are also heavily attenuated
I wonder if you all could point me if this a expected behaviour or something on my setup? If the latter, any suggestions where I should look into?
Thanks!
pu3hag
SDRDharp author (@lambdaprog) recently included a new AM splatter and co-channel QRM canceller. I've got some really cool results using KiwiSDR IQ demodulator, saving the recording to a WAV file and opening it on SDR#.
Next, I tried routing the KiwiSDR live audio out to SDRSharp (used Virtual Audio Cable). But I've got something unexpected for a IQ stream. It seems there a high-pass filter in effect notching the range around 0 to 70Hz on both left and right channels This effectively kills the AM carrier required by the canceller algorithm.
I found Firefox may pass audio thru an HPF under certain codecs. VAC has a Channel Mixing option. I toggled off both neither removed the HPF.
I also tried visualizing the live IQ out on Audacity and, sure enough, the lower 60-70Hz are also heavily attenuated
I wonder if you all could point me if this a expected behaviour or something on my setup? If the latter, any suggestions where I should look into?
Thanks!
pu3hag