DELAY DETECTION DEMODULATING SYSTEM

摘要

PURPOSE:To obtain a good demodulation characteristic by providing a multiplier in the preceding stage of a delay detector to obtain a frequency modulated wave of large frequency deviation and setting such delay time that the eye aperture of the delay detection output at a discrimination time is maximum and performing detection. CONSTITUTION:A digital signal 2 obtained as the output of a data generator 1 is applied to the modulating signal input terminal of a frequency modulator 3 to modulate the frequency of the carrier wave having a frequency fC with a modulation index (m) (m is a positive number). The output of this frequency modulator 3 reaches the reception side through a transmission line 4 and is inputted to a multiplier 5 to obtain a frequency modulated wave 6 having a carrier frequency NfC multiplied by N (N is a positive number). The frequency modulated wave 6 is detected by a delay detector 7 whose delay time is #c (#c is a positive number). It is sampled on a basis of a timing clock 11 obtained as the output of a timing reproducer 9 by a discriminator 10 and is discriminated to obtain a demodulated data output 12.