Frequency modulated signal demodulation process and demodulator putting this process into operation

Abstract

Abstract 1. Method of demodulating a signal which is frequency modulated about a frequency F and has a passband which is small in comparison to F, characterized in that the signal is sampled at a rhythm which is equal to 4F', F' being an arbitrary frequency of the frequency band of the signal ; in that one calculates the ratio N/D of a first linear combination N=x(t1 - 3/4F')-x(t1 ) - x(t1 - 2/4F') + x(t1 - 1/4F') and a second linear combination D=2.x(t1 - 2/4F'), - 2.x(t1 - 1/4F') of four successive samples : x(t1 ), x(t1 - 1/4F'), x(t1 - 2/4F'), x(t1 - 3/4F'), of the signal to be demodulated ; and in that one calculates 2F'/pi arc sin (N/D) this value corresponding to the value of the frequency variation delta F of the modulated signal.

Inventors

• 👤 André Marguinaud
• 👤 Max Artigalas
• 👤 Maurice Remy
• 👤 Jacques Sabatier

Bibliographic Details