Patent ID: 7650125
Filing Date: 2010-01-19
Classification: H04H,H04N

Abstract:
1. A system for demodulation of secondary audio program information, said system comprising: a bandpass filter for isolating said secondary audio program information from a composite audio signal; a Hilbert filter for producing a copy of said secondary audio program information with a phase shift; a delay module for delaying said secondary audio program information to produce a delayed copy of said secondary audio program information, wherein said delay module is capable of applying a non-unity delay to said secondary audio program information to produce said delayed copy of said secondary audio program information; and an FM demodulator for demodulating said secondary audio program information using a delay from said delay module and a discrete time index with a combination of said copy of said secondary audio program information with a phase shift and said delayed copy of said secondary audio program information to produce an FM demodulated signal.