Accession Number : ADD012332

Title :   Swept Acquisition for Pulsed Radio Frequency (RF) Phase Lock Loop.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Campbell,John T

Report Date : 12 Mar 1986

Pagination or Media Count : 38

Abstract : Swept acquisition of reference signals, including pulsed radio frequency radar waveforms, is achieved using sample-and-hold circuitry to track and hold in-phase and quadrature error signals (E1 and Eq) from a voltage controlled oscillator which is swept by a sweep generator. This presents a constant in-phase error signal to the integrator is the loop so that the phase lock loop may be implemented by conventional means. The quadrature error signal is filtered and compared with a threshold to determine when frequency lock has been obtained when the voltage control oscillator is swept at high speed. Then the voltage controlled oscillator is swept at a lower speed to distinguish the center lobe of the reference signal and attain phase lock. Finally, the voltage controlled oscillator is swept only while sampling the reference signal by gating the sweep rate signal with a sampling signal. This method enables one to acquire a pulsed radio frequency signal with jittered pulse repetition intervals while preventing locking on before or after the center frequency of the main lobe of the reference signal. (Patent Applications)

Descriptors :   *PATENT APPLICATIONS, *PHASE LOCKED SYSTEMS, *RADIOFREQUENCY PULSES, FREQUENCY, LOW VELOCITY, ERRORS, SIGNALS, CIRCUITS, SAMPLING, PULSE RATE, PULSE SPACING MODULATION, REPETITION RATE, LOOPS, RADIO SIGNALS, VOLTAGE CONTROLLED OSCILLATORS

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE