Amplitude, frequency or phase modulation device - has combination of modulators, mixers and filters to produce modulated output signal

摘要

The amplitude, frequency or phase modulation device receives a first signal (e) to be modulated respectively in amplitude, frequency or phase by a second modulating signal (a) to produce at its output a modulated signal (S). The device has an hormonic oscillator (6) which delivers a third signal (b) modulated respectively in amplitude, in frequency or in phase in a modulator (5) by the second signal (n) to produce at the output of the modulator a fourth modulated signal (b1). A first mixer (1) modulates the first signal (e) by the fourth signal (b1) to produce a signal (e1) which is fed through a high-pass filter (2) to produce a signal (e2) at the input of a second mixer (3). This signal is modulated by the third signal (b) to produce an output signal (e3) which is fed through a low pass filter (4) to produce the modulated output singal. Alternatively the first mixer (1) may receive the first signal (e) and the third signal (b), and the second mixer (3) the signal (e2) and the fourth signal (b1). Also the high-pass filter may be replaced by a low-pass filter (21) and the low-pass filter (4) by a high-pass filter (41).