On Saturday 21 January 2006 09:57 pm, Steve Rodgers wrote:
I'm not aware of any feature like this in GSM. With regard to DSP required, it would probably involve measuring the noise content of a signal. The problem is, that there's no easy way to determine noise from a valid signal when measuring energy and spectrum in band. What this means is you would probably have to get your signal quality from noise outside of the bandwidth of the channel similar to what happens with noise squelch circuits.
Well S/N voters work with just the audio from a link rx and cor. They do this using op amps that only amp the high frequency componits of a signal. This can be done with two op-amps fed into a comparator. There must be some way to code an op amp function in a DSP/CPU and have it out put a value for a signal with more highfrequency content in it.
Also, there is something else I forgot to mention in the issue list under Internet weather. There needs to be a way to adjust the delays dynamically between all of the receive channels so that when the voter switches audio channels, there is no repeated or dropped voice frames. This may not be a trivial exercise.
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