Accession Number : ADD015594
Title : Precision Digital Phase Lock Loop Circuit.
Descriptive Note : Patent, Filed 30 Aug 91, patented 20 Oct 92,
Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC
Personal Author(s) : Atwood, Kenneth L ; Pae, Peter K
Report Date : 20 Oct 1992
Pagination or Media Count : 10
Abstract : A digital PLL circuit has a serial shift register receiving input pulses and producing time-delayed output pulses, a clock generator applying clock pulses to the shift register to drive it and set the phase shift of the output pulses, and a digitally-controlled potentiometer connected in series with the clock generator and being adjustable to change its resistance in increments in order to adjust the resistance of the clock generator and thereby set the frequency of the clock pulses applied to the shift register and the time delay produced by the shift register. A feedback control arrangement receives the same digital input pulses as received by the shift register and detects the periods of the input pulses by counting to produce control pulses proportional to the detected periods. A ROM unit stores a lock-up table of values representing an array of different counts of increments by which the potentiometer resistance can be adjusted. The ROM unit can be accessed by input signals identifying different addresses thereof. The input signals are composed of the control pulses and other external pulses defining different desired phase shifts of the output pulses.
Descriptors : *PATENTS, *PHASE LOCKED SYSTEMS, *PHASE SHIFT, *LOOPS, *HYBRID CIRCUITS, *MICROCIRCUITS, ARRAYS, CIRCUITS, CLOCKS, CONTROL, DELAY, DRIVES, EXTERNAL, FEEDBACK, FREQUENCY, GENERATORS, INPUT, OUTPUT, PHASE, PHASE SHIFT, POTENTIOMETERS, PULSES, RESISTANCE, SHIFT REGISTERS, SIGNALS, STORES, TIME, VALUE, GRANTS
Subject Categories : Electrical and Electronic Equipment
Distribution Statement : APPROVED FOR PUBLIC RELEASE