Means and method for measuring the phase of an alternating electrical signal

Claim 2

Apparatus for measuring the phase angle between two alternating electrical signals, comprising: a. first and second input means for respectively receiving said two electrical signals; b. first circuit means coupled to said first input means for producing an output signal proportional to a first time interval between first and second reference points associated with one of said electrical signals; c. second circuit means coupled to said second input means for producing an output signal proportional to a second time interval between said first reference point and another reference point associated with the other of said electrical signals; d. dividing means coupled to said first and second circuit means for dividing the output signal of said second circuit means by the output signal of said first circuit means for providing an output signal from said dividing means representative of the ratio of said second time interval to said first time interval; and e. means coupled to said dividing means for indicating the phase angle between said electrical signals as a function of said ratio output signal.

Claim 3

The apparatus as described in claim 1 wherein said first and second reference points are the zero-crossing points of said one electrical signal, and said another reference point is a zero-crossing point of said other electrical signal.

Claim 4

The apparatus claimed in claim 1 wherein at least one of the alternating electrical signals is a sinusoidal signal.

Claim 5

The apparatus as described in claim 3 wherein both electrical signals are sinusoidal signals and wherein said first and second reference points are the peak amplitude points of said one sinusoidal signal, and said another reference point is a peak amplitude point of said other sinusoidal signal.

Claim 6

Phase-indicating apparatus, comprising: a. first source means for providing a reference signal of known frequency and phase; b. second source means for providing a signal of variable phase with respect to said reference signal; c. first integrator means for integrating a first DC voltage applied to said first integrator means to produce, at the output of said first integrator means, a constant-level voltage corresponding to the integration time of said first integrator means; d. second integrator means for integrating a second DC voltage applied to said second integrator means to produce, at the output of said second integrator means, a constant-level voltage corresponding to the integration time of said second integrator means; e. first means for producing a first output pulse in response to one portion of said reference signal and applying said output pulse to said first and second integrator means, thereby to simultaneously initiate the integration by each of said integrators; f. second means for producing a second output pulse in response to another portion of said reference signal and applying said output pulse to said first integrator means to terminate integration therein and to hold the output of said first integrator at a constant signal level; g. third means for producing a third output pulse in response to a portion of said variable-phase signal and applying said third output pulse to said second integrator means to terminate the integration of the other of said integrators and to hoLd the output of said second integrator at a constant signal level; h. means for dividing the output signal from said second integrator by the output signal from said first integrator, to provide a ratio signal; i. means coupled to said divider means for selectively sampling the ratio signal during the holding period of both the first and second integrators; and j. means for indicating the selectively sampled ratio signal.

Claim 7

Phase-indicating apparatus, comprising: a. first source means for providing a reference signal of known frequency and phase; b. second source means for providing a signal of variable phase with respect to said reference signal; c. first integrator means for integrating a first DC voltage applied to said first integrator means to produce, at the output of said first integrator means, a constant-level voltage corresponding to the integration time of said first integrator means; d. second integrator means for integrating a second DC voltage applied to said second integrator means to produce, at the output of said second integrator means, a constant-level voltage corresponding to the integration time of said second integrator means; e. first means for producing a first output pulse in response to one portion of said reference signal and applying said output pulse to said first and second integrator means, thereby to simultaneously initiate the integration by each of said integrators; f. second means for producing a second output pulse in response to another portion of said reference signal and applying said output pulse to said first integrator means to terminate integration therein and to hold the output of said first integrator at a constant signal level; g. third means for producing a third output pulse in response to a portion of said variable-phase signal and applying said third output pulse to said second integrator means to terminate the integration of the other of said integrators and to hoLd the output of said second integrator at a constant signal level; h. means for dividing the output signal from said second integrator by the output signal from said first integrator, to provide a ratio signal; i. means coupled to said divider means for selectively sampling the ratio signal during the holding period of both the first and second integrators; and j. means for indicating the selectively sampled ratio signal.

Claim 8

The apparatus as defined by claim 5 wherein said one and another portions of said reference signal are the zero-crossing points of a half-cycle of said reference signal, and the said portion of said variable-phase signal is the initial zero-crossing point of the half-cycle of said variable-phase signal.

Claim 9

Phase-measuring apparatus, comprising: a. a first source of reference signals having a known frequency and phase; b. a second source of signals having variable phase with respect to said reference signals; c. first trigger means coupled to said first source for providing stepped output signals corresponding to the positive and negative half-cycles of said reference signals; d. first and second integrator means having an integrate, hold, and reset mode; e. controlling means coupling said first trigger means to said first and second integrator means for initiating the integrate mode of said integrators, thereby to produce output signals from said integrators; f. hold means coupling said first trigger means to said first integrator means for terminating the integrating mode of said first integrator, thereby to hold the output signal from said first integrator at a constant value proportional to a first time interval of said half-cycle of said reference signal; g. second trigger means coupled to said second source for providing stepped output signals corresponding to the positive and negative half-cycles of said variable-phase signals; h. hold means coupling said second trigger means to said second integrator means for terminating the integrating mode of said second integrator, thereby to hold the output signal from said second integrator at a constant value proportional to a second time interval said variable-phase signals lags said reference signals; i. dividing means coupled to the outputs of said first and second integrator means for dividing the output signal from said second integrator by the output signal from said first integrator to provide a ratio signal at the output of said dividing means proportional to the ratio of said second time interval to said first time interval; j. sampling-and-holding means coupled to said dividing means for selecting, when triggered, specific portions of said ratio signal; k. means coupled to said first trigger means for triggering said sampling-and-holding means during the simultaneous hold modes of both of said integrators, thereby to produce a selected output signal from said sampling-and-holding means; and l. means coupled to said sampling-and-holding means for displaying said selected output signal.

Claim 10

Phase-measuring apparatus, comprising: a. a first source of reference signals having a known frequency and phase; b. a second source of signals having variable phase with respect to said reference signals; c. first trigger means coupled to said first source for providing stepped output signals corresponding to the positive and negative half-cycles of said reference signals; d. first and second integrator means having an integrate, hold, and reset mode; e. controlling means coupling said first trigger means to said first and second integrator means for initiating the integrate mode of said integrators, thereby to produce output signals from said integrators; f. hold means coupling said first trigger means to said first integrator means for terminating the integrating mode of said first integrator, thereby to hold the output signal from said first integrator at a constant value proportional to a first time interval of said half-cycle of said reference signal; g. second trigger means coupled to said second source for providing stepped output signals corresponding to the positive and negative half-cycles of said variable-phase signals; h. hold means coupling said second trigger means to said second integrator means for terminating the integrating mode of said second integrator, thereby to hold the output signal from said second integrator at a constant value proportional to a second time interval said variable-phase signals lags said reference signals; i. dividing means coupled to the outputs of said first and second integrator means for dividing the output signal from said second integrator by the output signal from said first integrator to provide a ratio signal at the output of said dividing means proportional to the ratio of said second time interval to said first time interval; j. sampling-and-holding means coupled to said dividing means for selecting, when triggered, specific portions of said ratio signal; k. means coupled to said first trigger means for triggering said sampling-and-holding means during the simultaneous hold modes of both of said integrators, thereby to produce a selected output signal from said sampling-and-holding means; and l. means coupled to said sampling-and-holding means for displaying said selected output signal.

Claim 11

The apparatus as described by claim 7 including reset means coupled to said first-mentioned holding means for resetting said first and second integrators.

Claim 12

The apparatus as described by claim 7 wherein said controlling means comprises a bistable flip-flop device triggered by the positive output signal from said first trigger means; said first-mentioned hold means is a single-shot multivibrator triggered by the negative output signal from said first trigger means and producing an output pulse having a specific pulse width, the said pulse width determining the duration of time the output signal from the first integrator is held constant; and said second-mentioned hold means comprises another bistable flip-flop device, the width of which output signal pulse determines the duration of time the output signal from the second integrator is held constant.

Claim 13

The apparatus as described by claim 9 wherein said triggeRing means coupled to said sample-and-hold means comprises at least one single-shot multivibrator having an output pulse triggered by the negative output signal from said first trigger means.

Claim 14

Apparatus for measuring the phase difference between two electrical signals which alternate about a given reference axis, comprising: a. first means for producing a voltage which corresponds in amplitude to a time interval determined by the first intersection of a first of said electrical signals with the reference axis and the second intersection of the same signal with the reference axis; b. second means for producing a voltage which corresponds in amplitude to a time interval related to the first intersection of the first electrical signal with the reference axis and the first intersection of the second electrical signal with the reference axis whereat the second electrical signal is changing in amplitude in the same direction that the first electrical signal was changing at the time the first electrical signal intersected said reference axis; c. dividing means for dividing the voltage produced by said second means by the voltage produced by said first means to provide a ratio voltage representative of the phase difference between said first and second signals; and d. means coupled to the dividing means for indicating the phase difference between the two electrical signals in response to the ratio voltage produced by said dividing means.

Claim 15

Apparatus for measuring the phase difference between two electrical signals which alternate about a given reference axis, comprising: a. first means for producing a voltage which corresponds in amplitude to a time interval determined by the first intersection of a first of said electrical signals with the reference axis and the second intersection of the same signal with the reference axis; b. second means for producing a voltage which corresponds in amplitude to a time interval related to the first intersection of the first electrical signal with the reference axis and the first intersection of the second electrical signal with the reference axis whereat the second electrical signal is changing in amplitude in the same direction that the first electrical signal was changing at the time the first electrical signal intersected said reference axis; c. dividing means for dividing the voltage produced by said second means by the voltage produced by said first means to provide a ratio voltage representative of the phase difference between said first and second signals; and d. means coupled to the dividing means for indicating the phase difference between the two electrical signals in response to the ratio voltage produced by said dividing means.

Claim 16

The apparatus claimed in claim 11 wherein the given reference axis is zero volts.

Claim 19

The method claimed in claim 14 wherein the given reference axis is zero volts.

Claim 20

The apparatus claimed in claim 11 wherein at least one of the two electrical signals is a sinusoidal signal.

Claim 21

The method claimed in claim 14 wherein at least one of the two electrical signals is a sinusoidal signal.

Claim 22

The method claimed in claim 14 wherein the first and second intermediate signals produced are, respectively, voltages corresponding in amplitude to the time intervals which they represent, and the ratio signal produced is a voltage corresponding to the ratio of the time intervals thus represented.