Two channel SAW spread spectrum transmission system for audio signals

Abstract

We have developed a two channel wireless audio transmission system applying a combination of frequency multiplex, frequency modulation, and SAW based spread spectrum technique. The coding/decoding is carried out asynchronously by a SAW phase shift keying filter. The acoustic devices have been fabricated on GaAs and LiTaO/sub 3/. The center frequency, bandwidth, code length, and code duration of the GaAs coder are 276 MHz, 48 MHz, 40 chip, and 1.4 /spl mu/s, respectively. The transmission was performed at the 2.4 GHz ISM band over a distance of 10 m with a transmission power less than 100 nW. A signal bandwidth of about 10 kHz per channel was achieved. The bit error rate of the transmission was 3/spl times/10/sup -8/. The rejection against jamming has been investigated.