Periodic signal analyzer using a randomly varied phase shifting circuit

A system for producing a signal indicative of the amplitude of a periodic signal for use by an amplitude responsive means, the system comprising:

• sampling means for periodically sampling said periodic signal at a sampling rate to form a digitally encoded signal;
• an all-pass filter, coupled to said sampling means, having a phase shift characteristic which varies as a function of an input number to produce a phase-varying sampled signal from said digitally encoded signal;
• a number generator, coupled to said all-pass filter, providing a succession of different input numbers thereto;
• absolute value means, coupled to said all-pass filter, for forming an absolute value signal from said phase-varying sampled signal;
• and
• averaging means, coupled to said absolute value means, for averaging said absolute value signal.

A method for producing a signal indicative of the amplitude of a periodic signal for use by an amplitude responsive device, the method comprising:

• periodically sampling said periodic signal at a sampling rate to form a digitally encoded signal;
• all-pass filtering said digitally encoded signal to impart a phase shift characteristic thereto which varies as a function of an input number to produce a phase-varying sampled signal from said digitally encoded signal;
• providing a succession of different input numbers for use during said all-pass filtering;
• forming an absolute value signal from said phase-varying sampled signal;
• and
• averaging said absolute value signal.

A system for measuring the amplitude of a periodic signal, comprising:

• means for sampling said periodic signal at a sampling rate to provide a sampled signal;
• means for applying a variable phase shift to said sampled signal to provide a variable phase-shifted sampled signal;
• means for processing said variable phase-shifted sampled signal to provide an average signal;
• and
• means for measuring the amplitude of said averaged signal.

A method of measuring the amplitude of a periodic signal, comprising:

• sampling said periodic signal at a sampling rate to provide a sampled signal;
• applying a variable phase shift to said sampled signal to provide a variable phase-shifted sampled signal;
• processing said variable phase-shifted sampled signal to provide an averaged signal;
• and
• amplitude measuring said averaged signal.