Comparison of non-FFT methods of TDM-FDM transmultiplexing

The comparison of different solutions not using FFT-type processors for the TDM-FDM conversion problem at the multiplex level (transmultiplexer) is considered. The analyzed solutions are: the bandpass method, the Hartley method, the Weaver method and a recently proposed new solution, the analytic signal method. Given specified conversion system performance, the comparison was carried out by considering the number of multiplications, the length of the digital data registers and the amount of digital memory. The obtained results for a FDM telephone standard group have shown the definite advantages of the analytic signal method. A complete set of comparison parameters for the different systems is reported and some spectral plots of the obtained system outputs are shown. Finally some future research trends in this field are indicated.