Accession Number : ADD008518

Title :   Digital Phase-Frequency Detector.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Kimsey,Thomas H

Report Date : 12 May 1981

Pagination or Media Count : 5

Abstract : A digital phase-frequency detector which provides rapid frequency acquisition and phase control when used in phase-locked loop applications. In a locked condition the output of a pair of flip-flop circuits are high causing an EXOR gate to produce a detector output, when unlocked a phase difference will increase until the higher frequency exhibits two positive transitions before one positive transition of the lower frequency can propagate through the circuit, this will cause the flip-flop receiving the higher frequency to change state thereby preventing the EXOR gate from gating and the other flip-flop from changing state, the flip-flop therefore controls the detector output until the two input frequencies again coincide and the output controlled by the EXOR gate. (Author)

Descriptors :   *Patents, *Phase locked systems, *Digital systems, *Frequency, *Acquisition, Phase control, Phased arrays, Quick reaction, Schematic diagrams, Logic circuits, Detectors, Voltage controlled oscillators, Open loop systems, Nand gates, Nor gates, Flip flop circuits

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE