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US 4,052,672 AGranted
Extended phase-range, high fidelity modulator arrangement
AssigneeMotorola, Inc.
InventorsRalph Thomas Enderby, Francis Robert Steel, Alan Michael Victor
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Abstract
An improved wideband phase modulator suitable as a simple modulation interface for existing phase modulated transmitters. The disclosed modulator arrangement utilizes a high stability reference oscillator and an associated phase locked loop for optimum long term stability. Means are included for extended phase range and high fidelity of modulation irrespective of loop bandwidth. Both tone and digital modulation is accommodated.
Claims5
An extended range, high fidelity phase modulator including in combination:
- a high stability reference oscillator:
- a phase locked loop comprising at least a phase detector, a lowpass filter, a frequency divider and a voltage controlled oscillator, said phase locked loop having a predetermined gain constant and providing a differentiating action for applied modulation components;
- means coupling said reference oscillator to said phase detector of said phase locked loop;
- first modulation input means for applying modulation signal components to the input of said voltage controlled oscillator;
- and
- second modulation input means for applying modified modulation signal components to said lowpass filter,
- said second modulation input means including integrating means having a gain constant substantially the reciprocal of said phase locked loop gain constant.
4 more elements
Dependencies are inferred from the claim text.