Patent ID: 6249179
Filing Date: 2001-06-19
Classification: H04L

Abstract:
A quadrature amplitude modulation (QAM) type demodulator comprising:an analog-to-digital converter receiving an input signal and producing a first signal,a baseband conversion circuit being electrically coupled to the analog-to-digital converter and receiving the first signal and producing a baseband signal, the baseband conversion circuit including a first direct digital synthesizer (DDS) circuit,a receive filter being electrically coupled to the baseband conversion circuit and receiving the baseband signal and producing a filtered baseband signal,a carrier recovery circuit being electrically coupled to the receive filter and receiving the filtered baseband signal and producing a QAM signal after filtering, the carrier recovery circuit including a second DDS circuit, anda symbol detection circuit being electrically coupled to the carrier recovery circuit and receiving the QAM signal after filtering,whereby an output signal of the symbol detection circuit is a demodulated data output signal.