Apparatus for phase measurement

Claim 1

An apparatus for calibrating a pulse width reading phasemeter, comprising: means for generating first and second consecutive pulses, wherein the pulses exist while a driving signal voltge is higher than a first calibrating voltage, and wherein both the end of the first pulse and the beginning of the second pulse occur when a reference signal crosses a second calibrating voltage on a positive transition; means for adjusting the relative phase between the driving and reference signals; means for determining when the first and second pulses have the same width; and means for generating a third pulse having a width proportional to the phase difference between the reference and driving signals.

Claim 2

An apparatus for calibrating a pulse width reading phasemeter, comprising: means for generating first and second consecutive pulses, wherein the pulses exist while a driving signal voltge is higher than a first calibrating voltage, and wherein both the end of the first pulse and the beginning of the second pulse occur when a reference signal crosses a second calibrating voltage on a positive transition; means for adjusting the relative phase between the driving and reference signals; means for determining when the first and second pulses have the same width; and means for generating a third pulse having a width proportional to the phase difference between the reference and driving signals.

Claim 4

An apparatus for determining the phase difference between a first and a second periodic waveform comprising: a first voltage comparator coupled to the first waveform, said first comparator having a square wave output which changes value at each zero crossing of the first waveform; a second voltage comparator coupled to the second waveform, said second comparator having a square wave output which changes value at each zero crossing of the second waveform; first and second pulse generators coupled to the output of said first comparator, wherein said first pulse generator generates a pulse at each positive going transition of the first comparator output, and said second pulse generator generates a pulse at each negative going transition of the first comparator output; a third pulse generator coupled to the output of said second comparator, said third generator generating a pulse at each positive going transition of the second comparator output; logic means coupled to the output of said second comparator and to the output of said first generator for generating a positive pulse synchronous with the first generator pulses which occur while the output of said second comparator is low; a first flip-flop having a first input coupled to the output of said first pulse generator and a second input coupled to the output of said third pulse generator; a second flip-flop having a first input coupled to the output of said second pulse generator and a second input coupled to the output of said third pulse generator; a third flip-flop having a first input coupled to the output of said logic means and having a second input coupled to the output of said third pulse generator; means for indicating the length of the output pulses generated by said first flip-flop; and, means coupled to the outputs of said second and third flip-flops for indicating when output pulses generated by said second and said third flip-flops have the same length.

Claim 5

An apparatus for determining the phase difference between a first and a second periodic waveform comprising: a first voltage comparator coupled to the first waveform, said first comparator having a square wave output which changes value at each zero crossing of the first waveform; a second voltage comparator coupled to the second waveform, said second comparator having a square wave output which changes value at each zero crossing of the second waveform; first and second pulse generators coupled to the output of said first comparator, wherein said first pulse generator generates a pulse at each positive going transition of the first comparator output, and said second pulse generator generates a pulse at each negative going transition of the first comparator output; a third pulse generator coupled to the output of said second comparator, said third generator generating a pulse at each positive going transition of the second comparator output; logic means coupled to the output of said second comparator and to the output of said first generator for generating a positive pulse synchronous with the first generator pulses which occur while the output of said second comparator is low; a first flip-flop having a first input coupled to the output of said first pulse generator and a second input coupled to the output of said third pulse generator; a second flip-flop having a first input coupled to the output of said second pulse generator and a second input coupled to the output of said third pulse generator; a third flip-flop having a first input coupled to the output of said logic means and having a second input coupled to the output of said third pulse generator; means for indicating the length of the output pulses generated by said first flip-flop; and, means coupled to the outputs of said second and third flip-flops for indicating when output pulses generated by said second and said third flip-flops have the same length.

Claim 6

A method for determining the phase relationship between a shaped signal and a reference signal, comprising the steps of: generating a first pulse having a width proportional to the phase difference between a positive transition of the shaped signal past a first calibrate voltage level and a positive transition of the reference signal past a second calibrate voltage; generating a second pulse having a width proportional to the phase difference between a positive transition of the reference signal past the second calibrate voltage and a negative transition of the shaped signal past the first calibrate voltage; adjusting the phase difference between the shaped and reference signals so that the first and second pulses have equal width; generating a third pulse having a width proportional to the phase difference between a positive transition of the shaped signal past the first calibrate voltage and a positive transition of the reference signal past the second calibrate voltage; and adjusting the first calibrate voltage level until the third pulse has a width of 90 degrees.

Claim 7

A method for determining the phase relationship between a shaped signal and a reference signal, comprising the steps of: generating a first pulse having a width proportional to the phase difference between a positive transition of the shaped signal past a first calibrate voltage level and a positive transition of the reference signal past a second calibrate voltage; generating a second pulse having a width proportional to the phase difference between a positive transition of the reference signal past the second calibrate voltage and a negative transition of the shaped signal past the first calibrate voltage; adjusting the phase difference between the shaped and reference signals so that the first and second pulses have equal width; generating a third pulse having a width proportional to the phase difference between a positive transition of the shaped signal past the first calibrate voltage and a positive transition of the reference signal past the second calibrate voltage; and adjusting the first calibrate voltage level until the third pulse has a width of 90 degrees.