Method and apparatus to evaluate audio equipment via filter banks for dynamic distortions and or differential phase and frequency modulation effects

An apparatus for measuring phase modulation or frequency modulation effects of a cross-modulation distortion product or signal from an audio device comprising:

• the audio device includes an input and an output;
• providing a first and a second signal;
• combining the first and second signal and coupling the first and the second signal to the input of the audio device;
• a filter including and input and an output;
• further comprising coupling the output of the audio device to the input of the filter, wherein the output of the filter includes a cross-modulation distortion signal ;
• and coupling the output of the filter to a phase detector or frequency modulation detector to measure for phase or frequency modulation distortion of a cross-modulation distortion product or signal.

A method for measuring phase modulation or frequency modulation effects of a cross-modulation distortion product or signal from an audio device comprising:

• the audio device includes an input and an output;
• providing a first and a second signal;
• combining the first and second signal and coupling the first and the second signal to the input of the audio device;
• a filter including and input and an output;
• further comprising coupling the output of the audio device to the input of the filter, wherein the output of the filter includes a cross-modulation distortion signal ;
• and coupling the output of the filter to a phase detector or frequency modulation detector to measure for phase or frequency modulation distortion of a cross-modulation distortion product or signal.