Accession Number : ADD012340

Title :   Phase Lock Acquisition System Having FLL for Coarse Tuning and PLL for Fine Tuning.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Caldwell,Stephen P ; Decker,Martin J ; Jelen,Robert A

Report Date : 01 Apr 1986

Pagination or Media Count : 7

Abstract : The acquisition of phase lock to a reference frequency by a signal acquisition system is accomplished using a voltage controlled oscillator, a wideband frequency discriminator, a prepositioning circuit, and a phase lock loop. The voltage controlled oscillator is prepositioned within a loop bandwidth of the reference frequency by the prepositioning circuit and the wide band frequency discriminator which provide coarse tuning. The voltage controlled oscillator achieves phase lock with the reference frequency when it receives the fine tune signal from the phase lock loop. Using both the discriminator and the phase lock loop allows fast acquisition without the need to calibrate the voltage controlled oscillator. Since the discriminator pull-in range is much larger than the phase-lock loop bandwidth, the number of bits can be much smaller than in acquisition circuit using a digital prepositioning circuit alone. (Author)

Descriptors :   *PATENTS, *PHASE LOCKED SYSTEMS, *DISCRIMINATORS, *VOLTAGE CONTROLLED OSCILLATORS, *ACQUISITION, *DETECTORS, TUNING, BANDWIDTH, CLOCKS, BROADBAND, DIGITAL TO ANALOG CONVERTERS, FREQUENCY, LOOPS, SIGNALS, CIRCUITS

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE