PROGRAMMABLE MULTI-MODE PHASE SENSITIVE VOLTMETER

• US 3,757,214 A
• Filed: 07/06/1971
• Issued: 09/04/1973
• Est. Priority Date: 07/06/1971
• Status: Expired due to Term

• Current Assignee: David L. Kaufman
• Original Assignee: David L. Kaufman
• Inventors: Kaufman, David L.
• Primary Examiner(s): Smith, Alfred E.
• Application Number:
  US05/160,002
• Time in Patent Office: 791 Days
• Field of Search: 324/83A,83D,83Q 328/155
• US Class Current: 324/76.78
• CPC Class Codes: G01R 19/0084 measuring voltage only all subgroups of G01R19/00 take precedence
• CPC Class Codes: G01R 19/25 using digital measurement techniques
• CPC Class Codes: G01R 19/2506 Arrangements for conditioning or analysing measured signals, e.g. for indicating peak values G01R19/003 takes precedence; Details concerning sampling, digitizing or waveform capturing displaying waveforms G01R13/00; analog sampling G01R19/0053
• CPC Class Codes: G01R 25/00 Arrangements for measuring phase angle between a voltage and a current or between voltages or currents

Abstract

Phase sensitive measurements of the fundamental component of a test signal having a complex waveform is performed in two distinct modes of operation using an unshifted and shifted sine wave reference signal. In each mode, the component is examined with respect to either the in-phase or quadrature phase of the reference signal. In measuring the total value of the fundamental component of the test signal with respect to the in-phase shifted reference signal, the reference signal is shifted, in a variable phase shifter having two wideband multipliers, in such a manner that the in phase component of the reference signal is maximized and the quadrature component of the reference signal is minimized. The test signal is multiplied by the in-phase shifted reference signal. The resulting signal is a measure of the total value of only the fundamental component of the test signal.

Claims

1. A phase sensitive voltmeter comprising:

a. first channel means for receiving a test signal;

b. second channel means for receiving a reference signal;

c. means operatively connected to said first and second channel means for phase shifting said reference signal with respect to said test signal;

d. detecting means operatively connected to said phase shifting means and said first and second channel means for generating signals representing test signal measurements; and

e. quadrant selector means operatively connected to said second channel means, detecting means, and phase shifter means for selecting the quadrant nearest said shifted reference signal.

2. The phase sensitive voltmeter as claimed in claim 1 including:

a. first phase lock loop means operatively connected to said second channel means, quadrant selector means, and means for generating at least two unshifted signal in quadrature phase with respect to each other; and

b. second phase lock loop means operatively connected to said phase shifter means and detecting means for generating at least two shifted signals in quadrature phase with respect to each other.

3. The phase sensitive voltmeter as claimed in claim 2 wherein said phase shifter means includes:

a. sine function generator means operatively connected to said detecting means;

b. cosine function generator means operatively connected to said detecting means;

c. first analog multiplier means operatively connected to said sine function generator means and said second phase lock loop means, said first analog multiplier means of said shifted signals from said second phase lock loop means;

d. second analog multiplier means operatively connected to said cosine function generator means and said second phase lock loop means, said second analog multiplier means of said shifted signals from said second phase lock loop means;

e. first summing means operatively connected to said first and second analog multiplier means for adding the signal at the output of each said analog multiplier means; and

f. second summing means operatively connected tr said first summing means and said second phase lock loop means, said second summing means operating to add the signal at said first summing means and said other shifted signal from said second phase shifter means;

g. said phase shifting means operating over a wide frequency range without tuning.

4. A phase sensitive voltmeter comprising:

a. first channel means for receiving a test signal;

b. second channel means for receiving a reference signal;

c. means operatively connected to said first and second channel means for phase shifting said reference signal with respect to said test signal; and

d. detecting means operatively connected to said phase shifting means and said first and second channel means for generating signals representing test signal measurements, said detecting means including at least one analog multiplier.

5. A phase sensitive voltmeter comprising:

a. first channel means for receiving a test signal;

b. second channel means for receiving a reference signal;

c. means operatively connected to said first and second channel means for phase shifting said reference signal with respect to said test signal; and

d. detecting means operatively connected to said phase shifting means and said first and second channel means for generating signals representing test signal measurements, said detecting means including full wave detector means and at least four analog multiplier means.

6. The phase sensitive voltmeter as claimed in claim 5 including function selector means having input and output terminal means, said input terminal means operatively connected to said full wave detector means and analog multiplier means for selectively controlling the measured test signal presented at said output terminal means.

7. A phase sensitive voltmeter comprising:

a. first channel means for receiving a test signal having a complex waveform;

b. second channel means for receiving a sinusoidal reference signal;

c. first phase lock loop means operatively connected to said second channel means for generating at least two unshifted signals in quadrature phase with respect to each other;

d. detecting means having input and output terminal means said input terminal means operatively connected to said first phase lock loop means and said first channel means, said detecting means generating signals representing test signal measurements with respect to said reference signal said test signal measurements presented at said output terminal means;

e. quadrant selector means operatively connected to said first phase lock loop means and said output terminal means of said detecting means;

f. phase shifter means operatively connected to said quadrant selector means first and detecting means for phase shifting said reference signal with respect to said test signal; and

g. second phase lock loop means operatively connected to said phase shifter means and said input terminal means of said detecting means, said second phase lock loop means generating at least two shifted signals in quadrature with respect to eachother;

h. said quadrant selector means selecting the quadrant nearest said shifted reference signal.

8. The phase sensitive voltmeter as claimed in claim 7 including a function selector means having input and output terminal means, said input terminal means of said function selector means operatively connected to said detecting means for selectively controlling the measured test signal presented at said output terminal of said function selector means.

9. The phase sensitive voltmeter as claimed in claim 7 wherein said detecting means includeS at least first, second, third, and fourth analog multiplier means, each said analog multiplier means having first and second input terminal means and an output terminal means, said first input terminal means of each said analog multiplier means operatively connected to said first channel means, said second input terminal means of said first and second analog multiplier means operatively connected to said first phase lock loop means, said second input terminal means of said third and fourth analog multiplier means operatively connected to said second phase lock loop means, said output terminal means of said first and second analog multiplier means operatively connected to said quadrant selector means, said output terminal means of said fourth analog multiplier means operatively connected to said phase shifter means, phase sensitive test signal measurements being presented at said output terminal means of each said analog multiplier means, said phase sensitive test signal measurement presented at said output terminal means of said first analog multiplier means being an in-phase test signal component with respect to said unshifted reference signal, said phase sensitive test signal measurement presented at said output terminal means of said second analog multiplier means being a quadrature phase test signal component with respect to said unshifted reference signal, said phase sensitive test signal measurement presented at said output terminal means of said third analog multiplier means being an in-phase test signal component with respect to said shifted reference signal, and said phase sensitive test signal measurement presented at said output terminal means of said fourth analog multiplier means being a quadrature phase test signal component with respect to said shifted reference signal.

10. The phase sensitive voltmeter as claimed in claim 9 including error amplifier means having input and output terminal means, said error amplifier input terminal means operatively connected to said output terminal means of said fourth analog multiplier means, said error amplifier output terminal means operatively connected to said phase shifter means, said error amplifier means generating a signal for controlling said phase shifter means.

11. The phase sensitive voltmeter as claimed in claim 10 wherein said phase shifter means includes:

a. sine function generator means having input and output terminals, said sine function generator input terminal operatively connected to said error amplifier output terminal means;

b. cosine function generator means having input and output terminals, said cosine function generator input terminal operatively connected to said error amplifier output terminal means;

c. fifth analog multiplier means having first and second input terminals and an output terminal, said fifth analog multiplier means first input terminal operatively connected to said output terminal of said sine function generator means, said second input terminal of said fifth analog multipliers operatively connected to said quadrant selector means;

d. sixth analog multiplier means having first and second input terminals and an output terminal, said sixth analog multiplier means first input terminal operatively connected to said output terminal of said cosine function generator means, said second input terminal of said sixth analog multiplier means operatively connected to said quadrant selector means;

e. first summing means operatively connected to said output terminals of said fifth and sixth analog multiplier means for adding the signal at said output terminals of each said fifth and sixth analog multiplier means;

f. second summing means operatively connected to said first summing means and said second input terminal of said sixth analog multiplier means for adding the signals at said first summing means and quadrant selector means.