Digital demodulator which quantizes signal components according to different thresholds
AssigneeAgence Spatiale Europeenne
InventorAlain Zarembowitch
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Abstract
There is disclosed a digital demodulator for the demodulation of an m-phase shift keying modulated signal. The demodulator comprises a sampling and quantizing circuit which samples and quantizes in-phase and in-quadrature components of the modulated analog signal and a carrier recovery circuit for reconstructing the carrier. The sampling and quantizing circuit quantizes the in-phase and in-quadrature components by means of a number of different quantization thresholds. This device is used in communications systems, particularly terrestrial and satellite microwave links and computer-to-computer links.
Claims8
A digital receiver apparatus for the demodulation of a multi-state phase shift keying modulated signal comprising:
- first sampling and quantizing means having a plurality of first quantization elements connected and arranged to receive the in-phase component of a modulated analog input signal and to produce quantized samples of said in-phase component according to different quantization thresholds,
- second sampling and quantizing means having a plurality of second quantization elements connected and arranged to receive the in-quadrature component of said modulated analog input signal and t produce quantized samples of said in quadrature component according to said different quantization thresholds,
- said first and second sampling and quantizing means being constructed and arranged to produce quantized samples of the phase of the received signal, and
- a carrier recovery circuit connected to receive signals corresponding to the quantized samples of the phase of the received signal to reconstruct the carrier for demodulating the received signal.
Dependencies are inferred from the claim text.