On receive, audio DSP takes audio from the receiver's detector and possibly feeds it back into the audio stages. On transmit, the DSP gets it's audio from your microphone and feeds the processed audio directly into the radio's modulator. In both cases, you bypass any audio processing within the radio.
DSP on HF receivers is done either at signal (RF) frequency or at the radio's intermediate frequency.
In either case you're unlikely to do it with a standard hand held radio without some surgery.
You can buy VHF/UHF data radios without and audio stages.
If you want to inject video data, or data with a similar bandwedth then you're looking for a radio with an IF 6-10MHz wide. Available but uncommon.
Also, this has no connection with a Chirp egroup. Chirp is software for programming the memories of your regular voice radio.
On 07/04/2021 17:50 Robert Withers robert.withers@pm.me wrote:
An additional query. How is DSP done, then? I thought that is what I was looking to do, with a program running on connected computers, doing the processing of the digital data.