International Telemetering Conference Proceedings / October 28-31, 1985 / Riviera Hotel, Las Vegas, NevadaA unified approach to the multiplex is proposed in terms of the orthogonal functions. It is called quadrature division multiplex, or Q D M in short. The orthogonal function is essential to the multiplex. Except these functions mentioned above, there are other orthogonal functions which are suitable for engineering practice. The orthogonality of the functions is used for the division of signals. A block diagram of Q D M is briefly described. The perfomances of the Q D M system are analysed. The speciality of the Q D M is simple and good. A model of the Q D M is built in our laboratory. A New type of bridge function is presented. It is ca...