I am an unapologetic audio snob. Thus, I strive to always get the best sound possible out of my nodes.
A while back, I discovered that, if a radio has discriminator output, I could disable the highpass filter in either simpleusb or usbradio, which has a slight resonant bump at 300 hz, out of line, then insert a notch filter at the PL tone frequency in rpt.conf, resulting in a much smoother and fuller sound on RX. Unfortunately, this means DTMF decoding doesn’t work, because the decoder in the module hears that constant sine wave from the PL tone, which throws it off.
So, I’m wondering, given the current implementation of things, if there is a way to stick a notch filter in usbradio before the decoding stage, while still otherwise not having a highpass filter in-line, or if this requires a change in the DSP.
Not sure who besides me even cares, really.