Device for continuous phase modulation by frequency synthesizer with phase-locked loop

摘要

PCT No. PCT/FR95/00129 Sec. 371 Date Aug. 7, 1996 Sec. 102(e) Date Aug. 7, 1996 PCT Filed Feb. 2, 1995 PCT Pub. No. WO95/22196 PCT Pub. Date Aug. 17, 1995Device for continuous phase modulation, produced from a frequency synthesizer including a variable oscillator and a phase-locked loop with, in series, a frequency division circuit, a phase comparator and a low-pass filter. In order to reduce modulation in the loop, the modulation is applied not only to the input of the synthesizer but also, in compensation, in the loop. In order to eliminate the modulation residue in the loop, a control signal for the oscillator is derived by a circuit which performs a correlation between the residue of the modulation and the output signal from a filter producing the same filtering effect as the loop, and which receives the modulation signal from the input of the synthesizer.