Nowhere does it say what the DSP settings are, what the changes would actually do and what situations they should be changed
I have to agree on that. There's no advise how to adjust the parameters and how you can detect if one setting needs to be adjusted.
The DSP and ADC only works for P25 modulation and not for NXDN and DMR. I don't know if that's a bug or are done intentionally to not allow adjustments in other protocols. ADC are the audio level to the decoder chip and if you are familiar with DSD+ you feed that software with an audio signal from a receiver and that receiver can usually be adjusted in volume level. To be useful the ADC really needs to be set individually for each site and not globally as it is now.
The DSP setting I believe have been explained as being the sampling rate that the DSP processor uses to sample the digital signal but I do not know why its highest setting are not the best. I haven't seen any other explanation for the DSP than being sample rate but it would make more sense if it where the level where it detects the signal, on just the top and the bottom of the signal curve or more towards the middle center line. Then the middle of the road level would be the best for a clean strong signal and a noisy weak signal could need a lower value and an interfered signal, like in simulcast, could need the highest value, but where it still decodes, by testing the highest value and then lower it in steps until it starts to decode.
Zeromatic are the function to let the scanner only react to frequencies that are spot on. In scanners that do not have that function you can often receive distorted signals from an adjacent frequency if they are strong enough. Every FM demodulators has a DC voltage component that follows the frequency carrier. If the frequency are spot on the DC voltage are exactly in the middle of the range. Whistler assumes this to be 1180mV. When the frequency drift to the side, slightly higher or lower in frequency, the DC voltage will change. My TRX-2 scanner are off by 1KHz in the 400MHz band and I would need to change that 1180mV to some other value to make that a new center point. It's probably some hidden service mode that can show the current DC voltage when monitoring a known good frequency reference and then set the Threshold correctly.
The Slope setting tells how much the voltage will change when the frequency are off and will make the window where it accepts the frequency to be correct either more narrow or wider. The Delay have to be used to let the scanners receiver settle down after a frequency change and could take different times dependent of component tolerances. If setting the time too short it could discard a correct frequency as being off by too much but having it too long will probably hamper scanning rate and also unmute the audio too late.
/Ubbe
