A TELEMETRY SYSTEM USING WALSH FUNCTIONS WITH IMPROVEMENTS IN ACCURACY

Abstract

A telemetry system based on Walsh functions has been developed since 1980.[1.2] The systerm is called sequency division multiplex, or SDM. A prototype of the system hss been assembled and a lot of laboratory tests are also made in recent 2 or 3 years. Of course, in order to put this system into real use, some practical problems still remain to be solved. In this paper the system design measures taken to improve the accuracy and some new a snchronization methods we adopted are described. Since the choice of subcarriers is very important in designing a telemetry system, a table of recommended sequence values of the walsh functions for subcarriers of the telemetry system is presented. Since the vibration signal in high frequency band is produced in many cases, it is necessary to build a system which can measure this signal. The frequency response of each channel is 2000 Hz , it will have wide applications in industrial automation.