Kingsley W Craft

US Patent:

43217060, Mar 23, 1982

Filed:

Jul 14, 1980

Appl. No.:

6/168524

Inventors:

Kingsley W. Craft - Woodinville WA

Assignee:

John Fluke Mfg. Co., Inc. - Mountlake Terrace WA

International Classification:

H04B 104
H03B 304
H04L 2712
H04L 2720

US Classification:

375 59

Abstract:

A programmable phase-locked loop frequency synthesizer having a feedback path that includes a tuned discriminator circuit is frequency modulated by coupling a portion of the modulating signal into the feedback path to effect modulation at rates which exceed the bandwidth of the phase-locked loop and by utilizing a portion of the modulating signal to frequency modulate the phase-locked loop reference signal to effect modulation at rates within the bandwidth of the phase-locked loop. A digitally controlled phase shifter that forms a portion of the discriminator tuning circuits in effect divides the phase-locked loop tuning range into a series of relatively narrow centiguous frequency bands. Data, representing deviations in the discriminator characteristics for each of these frequency bands, are stored in an erasable programmable read only memory. As the phase-locked loop is tuned to a particular frequency, a microprocessor determines the associated frequency band, accesses the stored data appropriate to that frequency band and establishes the proper setting of the digitally controlled phase shifter.