Patent ID: 7853021
Filing Date: 2010-12-14
Classification: H04B,H04L,H04N

Abstract:
1. A decoding apparatus for decoding an analog audio signal, the decoding apparatus comprising: an RF tuner for receiving the analog audio signal and providing an analog sound intercarrier frequency (SIF) signal indicative thereof, the carrier center frequency of the analog audio signal is a first carrier frequency, and the carrier center frequency of the analog SIF signal is a second carrier frequency; an analog to digital (A/D) converter for sampling the analog SIF signal at a sample rate at least twice the second carrier frequency and converting the analog SIF signal into a digital SIF signal, and the carrier center frequency of the digital SIF signal substantially remaining the same as the second carrier frequency; a mixer for mixing the digital SIF signal with a local oscillation signal to remove the carrier of the digital SIF signal and generate a mixed digital SIF signal; a filter for filtering the noise of the mixed digital SIF signal to generate a filter signal; a digital down sampling device for down sampling the filter signal to generate a baseband signal; and a programmable digital signal processor (DSP) for demodulating the baseband signal according to a demodulation procedure of a predetermined standard, and decoding the demodulated baseband signal to output an output signal in compliance with a decoding procedure of the predetermined standard; wherein the programmable digital signal processor further outputs a carrier recovery signal to the mixer in order to adjust the local oscillation signal enabling to output an adjusted baseband signal by the digital down sampling device, wherein an average level value of the adjusted baseband signal comports with a predetermined level value.