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Linear Phase Detector With Digital Circuits

IP.com Disclosure Number: IPCOM000079208D
Original Publication Date: 1973-May-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Torrey, WD: AUTHOR

Abstract

Fig. 1 shows a digitally organized phase detector, with output linearly related to the phase different between two phase comparable input waveforms V(IN) and V(REF). The frequency F1 of V(IN) is a predetermined submultiple of the frequency 4F1 of V(REF).

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Linear Phase Detector With Digital Circuits

Fig. 1 shows a digitally organized phase detector, with output linearly related to the phase different between two phase comparable input waveforms V(IN) and V(REF). The frequency F1 of V(IN) is a predetermined submultiple of the frequency 4F1 of V(REF).

V(REF) is shifted or otherwise logically manipulated by circuits 3 to produce cyclic signal waveforms 0 degrees, 90 degrees, 180 degrees and 270 degrees, shown Fig. 2, having frequency F1 and staggered time-overlapped phase. AND circuits 5,7, conditioned, respectively, by the 270 degrees and 90 degree signals, sample V(IN) at respective phase positions producing respective sampled waveforms V1, V2 shown in Fig. 2. Difference amplifier 9 and low-pass filter 11 convert the sampled waveforms into analog DC voltage Vx representing the phase difference between V(IN) and 0 degrees reference waveform.

Vx may be used as a control function for phase-locked loop demodulation applications requiring precise linear characteristics.

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