qpsk modulator circuit
QPSK Demodulation and Audio Signal-Processing IC for Satellite Broadcast Reception using LC7851E
The LC7851E demodulates the QPSK (quadrature phase shift keying) modulated audio data broadcast by the Japanese BS and CS broadcast satellites and converts that data to an analog audio signal. This IC integrates on a single chip the audio system signal precessing required foe BS and CS receivers from QPSK demodulation to analog audio reproduction. The main functions provided by the LC7851E include QPSK demodulation, differential decoding conversion, descrambling, deinterleaving, and error correction. It also generates a PCM audio signal. The PCM audio signal is converted to an analog audio signal by on-chip digital filters and A/D converters.
QPSK demodulator, PCM decoder, digital filters, D/A converters, and operational amplifiers integrated on a single chip.
The nimber of required external components has been reduced and adjusment-free operation achieved in the QPSK demodulator by implementing that block as a digital circuit on a single chip.
CPU interface/ interface circuit.