In addition, I discovered almost immediately that too much audio
drive into the radio for digital modes will inhibit transmit.? I
thought something was wrong with my QMX when it wouldn't transmit
but for a brief second, but when I turned down the audio drive to
100% (Linux pavumixer) it behaved normally.? Presumably it can
overwhelm the ADC.? The audio was turned up for another
application but the laptop thought it applied to the QMX as well.
There is no ADC involved. All transfer from the PC to the QMX is digital via the USB audio sound card emulation of QMX. So what happens if you have a sinewave at full 100.0% volume, the sinewave peaks and troughs hit the peak numbers the digital transfer is capable of. If you go beyond that, then the peaks "wrap around" so you then get a frequency component at even harmonics, at a lower amplitude; QMX will then measure the incorrect frequency, as well as determine that the amplitude (of those wrapped peaks) is below the threshold and it will switch off the transmit.?
