Browse Prior Art Database

Variable Phase Signal Generator

IP.com Disclosure Number: IPCOM000078838D
Original Publication Date: 1973-Mar-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 3 page(s) / 60K

Publishing Venue

IBM

Related People

Buhler, OR: AUTHOR

Abstract

This signal generator develops two square-wave signals of identical frequency. The phase displacement between these two signals is continuously variable from -180 degrees to +180 degrees.

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Variable Phase Signal Generator

This signal generator develops two square-wave signals of identical frequency. The phase displacement between these two signals is continuously variable from -180 degrees to +180 degrees.

The triangle and square-wave generator of Fig. 1 generates the three voltage waveforms shown in Fig. 2, as associated with conductors 10, 11 and 12, respectively. These three waveforms are required inputs to the variable-phase signal generator of Fig. 2. The triangular waveform is generated by cyclic charging and discharging of capacitor 13, as this capacitor is cyclically connected to one of the current sources 14 or 15 and disconnected from the other source. This cyclic switching operation is controlled by latch 16. The set and reset inputs of latch 16 are controlled by voltage comparators 17 and 18. Comparator 17 compares a positive capacitor voltage at terminal 19 to positive reference voltage
20. Comparator 18 compares a negative voltage at terminal 19 to negative reference voltage 21. When the required comparison is made, latch 16 assumes its alternate state and switches 22, 23 operate to begin a discharge-recharge cycle of capacitor 13. In this manner, triangle waveform 10 and the two complementary square waveforms 11 and 12 are generated.

The triangle waveform is used in Fig. 2 to control the frequency of the two variable-phase square-wave signals which appear on conductors 24, 32. The triangle waveform is also a time-variable voltage whose magnitude is used to variably control the phase of these two signals, in accordance with a phase control input voltage.

The two complementary square waveforms control the enabling of the proper one of four AND's ass...