ITU G.711 codec, for speech waveform

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Hi.. I am trying to design modem to sent speech signal, I used codec G.711 with bit rate 64 Kbps but I am confused do I need to use a compression ratio? And what is the best value for this ratio?

Thanks

 

[zorro]

Hi,

The term "compression" in this context does not refer to "data compression" intended to reduce volume of data, but with coding instantaneous values of the signal in order to manage a wide dynamic range.
The digitized values don't follow a linear relationship with the analog values. For example, the number representing an instantaneous value of 1V is not twice the the number representing an instantaneous value of 0.5V; it's smaller. Higher values are compressed according to a quasi-logarithmic function.
Regards

Z