• A NEW ORTHOGONAL MULTIPLEX SYSTEM

      shan, Zhang Qi; Zhihua, Li; Beijing Institute of Aeronautics and Astronautics; Qinghua University (International Foundation for Telemetering, 1982-09)
      The basis of mathematics which can form a telemetering system is orthogonal functions. Three kinds of orthogonal functions are used up to now. First of them is sine and cosine functions. Second one is block pulse functions. The third one is walsh functions. Their corresponding systems are FDM, TDM and SDM. There are also other orthogonal sets which can form telemetering system, such as Legendre polynomials and Hermite polynomials. Hewever. They are too complex for engineering practice. Except these functions mentioned above, is there any other orthogonal functions which is suitable for engineering practice? In this paper we presented a new type of orthogonal functions. Its construction is similar to Walsh functions. The amplitudes of the functions are +1, -1 and 0. In the sence that they close the gap between walsh functions and block functions, it is called Bride functions. The definition and properties are discussed in more detail here. The construction of system is also similar to that of SDM.
    • A TELEMETRY SYSTEM USING WALSH FUNCTIONS WITH IMPROVEMENTS IN ACCURACY

      Feng, Ju; Beijing Institute of Aeronautics and Astronautics (International Foundation for Telemetering, 1982-09)
      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.