In methods and apparatus for assessing voice quality in AMPS cellular radio systems, a signal-to-noise ratio is estimated for a SAT signal of an RF channel, and the voice quality of the RF channel is inferred from the SAT signal-to-noise ratio. ...http://www.google.com/patents/US5710791?utm_source=gb-gplus-sharePatent US5710791 - Methods and apparatus for predicting voice quality in AMPS cellular radio systems 
