US 3,947,777 AGranted

Circuit arrangement for the demodulation of a phase-modulated signal

AssigneeSiemens Aktiengesellschaft

InventorErich Burger

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Abstract

Apparatus for demodulating phase modulated signals is described. The latter signals are produced by modulation of a carrier or harmonically related carriers. The modulated signal, constituted by consecutive modulation sections, is coupled to an analogue multiplier, the output of which is connected to an integrator. The integrator produces the demodulated signal. A pulse generator produces a sequence of pulses, each of which occurs within a given modulation section. The duration of each pulse equals the reciprocal of the fundamental frequency. A carrier corresponding in frequency and synchronized with the transmitted carrier is produced in the receiver. The transmitted carrier and receiver-produced carrier are coupled to the multiplier. The latter carrier is switched prior to its application to the multiplier using the output of the pulse generator.

Claims7

Dependent claims

In apparatus in a receiver for demodulating a phase modulated signal, which signal is constituted by at least one carrier and a consecutive series of modulation section, wherein the received modulated signal is coupled to an analogue multiplier, the output of which is coupled to an integrator which emits a demodulated signal, the improvement comprising:

first pulse generator means for producing a sequence of rectangular pulses, each of which occurs within a different one of said modulation sections, said pulses being of a duration equal to the reciprocal of the fundamental frequency of the carrier,
means in the receiver for generating a local carrier signal corresponding in frequency with the carrier signal of said received modulated signal and in phase therewith, and
switching means for connecting said local carrier signal to said multiplier, said switching means being operable to connect said local carrier signal to said multiplier responsive to the output of said pulse generator means,
said multiplier producing an output having a value which is the product of said received carrier signal and said switched local carrier signal.

1 more element

Dependencies are inferred from the claim text.