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(Previously posted in Amateur Radio: https://ham.stackexchange.com/questions/7335/how-does-dab-radio-garbled-noise-come-about )

I've been fascinated by my digital/DAB radio lately, whose placement in my kitchen causes the signal to falter in certain circumstances, producing garbled/burbling/bubbling speech-like noise like this:

I want to approximate this effect on live speech.

I wondered if anyone sufficiently knows the ins and outs of digital radio codecs to explain how they lead to the specific sound of these artefacts? Often it sounds kind of like short bursts of different kinds of noise put through a vocoder - I imagine there is some kind of encoding of vocoded/LPC/ATS-style speech data that is received separately from the full frequency signal. So my first attempt will involve random short bursts of noise put through a vocoder - but maybe I could get some clues as to what the nature of the noise should be?

  • The vocoder idea is worth a try. To be able to analyze what is going on here, I would need a file with better quality. Can you maybe offer a HQ download? – philburns May 2 '17 at 8:51
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The simplest way to achieve what you are looking for is to undertake the following workflow:

  1. identify a similar type of audio codec
  2. encode a stream of audio
  3. implement an algorithm to randomly corrupt the data-stream in varying levels of severity
  4. decode the corrupted data stream to audio
  5. listen.
  • 1
    Thanks for the suggestion, but I wouldn't know where to start either identifying the codec or encoding/decoding. In the end, I got a very good approximation to this by putting pink noise through a vocoder and a hard gate. – Igid Nov 18 '18 at 10:18
  • why not take a look at GNURadio? this is a very useful way to simulate digital radio encoding blocks. It may well be possible to implement a very simple DAB Coding-Decoding graph into which you can then insert some way of corrupting the encoded data directly. GNURadio is definitely worth a look and as a radio ham, this tool should definitely be in your arsenal for any future SDR work and investigation. – Mark Dec 16 '18 at 14:22

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