FM data demodulator including circuit for eliminating step distortion
AssigneeSiemens Aktiengesellschaft
InventorWerner Paetsch
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Abstract
A circuit arrangement is disclosed for the correction of step distortions in a transmission of data employing frequency-modulated data signals. The circuit arrangement contains a demodulator which compares time durations between edges of the frequency-modulated data signals with a measuring time duration generated in a timing element and generates demodulated data signals after an integration. The demodulated data signals are compared in a comparator to reference signals and the signals at the output of the comparator are integrated in an integration element. The integration element emits control signals to the timing element. With these control signals the measuring time duration is changed in such manner that the step distortions of the demodulated data signals are opposed.
Claims6
A circuit arrangement for the correction of step distortions of given step frequency in a transmission of data by use of frequency-modulated data signals, comprising:
- demodulator means for comparing time durations between edges of the frequency-modulated data signals with a measuring time duration generated by a timing element in the demodulator means, said demodulator means generating filtered demodulated data signals which have step distortions as a result of frequency deviations of the frequency-modulated data signals;
- comparator means for comparing momentary values of the demodulated data signals with momentary values of reference signals generated by a clock pulse generator whose repetition rate is equal to twice the step frequency of the demodulated data signals;
- and
- integration means for integrating an output signal fo said comparator means and emitting control signals to said demodulator means, said control signal being fed to the timing element to oppose said step distortions of the demodulated data signals by changing the measuring time duration of the timing element.
Dependencies are inferred from the claim text.