Title :
SAW-correlator module for spread-spectrum DPSK asynchronous demodulation
Author :
Schelbert, Peter G.
Author_Institution :
ETH-Inst. for Field Theory & High Frequency Tech., Zurich, Switzerland
Abstract :
Details of the design and performance of a SAW (surface acoustic wave) correlator module for the demodulation of a direct sequence DPSK (differential phase shift keying) modulated spread-spectrum signal are presented. In contrast to convolver solutions, neither reference code nor synchronization is needed. This leads to a low system complexity and a high electromagnetic interference immunity. The module consists of two parallel SAW correlators on one chip. The preprocessed correlator outputs allow easy detection of the data bits. The cross-correlation time-sidelobes are minimized by additional taps and appropriate weighting. A bandpass-function with sharp cutoff is integrated in the correlators without degrading demodulation performance. The center frequency is 217 MHz, the chip-rate is 25.75 Mchip/s, and the data rate is 250 kb/s. Multipaths up to 4 μs are suppressed
Keywords :
acoustic signal processing; correlators; demodulation; modules; phase shift keying; spread spectrum communication; surface acoustic wave filters; 217 MHz; 250 kbit/s; SAW-correlator module; asynchronous demodulation; bandpass-function; charge distribution model; design; high electromagnetic interference immunity; low system complexity; multipath fading suppression; parallel SAW correlators; performance; sharp cutoff; spread-spectrum DPSK; Acoustic waves; Convolvers; Correlators; Demodulation; Differential phase shift keying; Differential quadrature phase shift keying; Phase modulation; Signal design; Spread spectrum communication; Surface acoustic waves;
Conference_Titel :
Ultrasonics Symposium, 1990. Proceedings., IEEE 1990
Conference_Location :
Honolulu, HI
DOI :
10.1109/ULTSYM.1990.171341
