Frequency-tracked synthesizer employing selective harmonic amplification and/or frequency scaling

An apparatus for tracking the fundamental frequency of an analog signal for controlling the clock signal rate of a DSP system receiving the analog signal, to be a constant integer multiple of that fundamental frequency;

• the apparatus comprising:
• a fundamental frequency detector generating a sine wave running at said fundamental frequency;
• and
• a frequency multiplier receiving said fundamental frequency sine wave and generating said clock signal of said DSP system therefrom.

In combination with a digital signal processor connected to an analog-to-digital converter for generating a digital representation of an analog signal to be acted upon by the digital signal processor;

• an apparatus for controlling a clock signal used by the digital signal processor, the apparatus comprising:
• a detector for generating a sine wave having a frequency that is the fundamental frequency of said analog signal;
• and
• a frequency multiplier for generating said clock signal at a frequency which is a precise selected multiple of said fundamental frequency of said sine wave.

A music synthesizer for modifying a monophonic analog signal having a fundamental frequency;

• the synthesizer comprising:
• an analog-to-digital converter for digitizing said monophonic analog signal;
• a plurality of harmonic selectors, each such selector having a filter for passing only a selected harmonic component of said digitized analog signal;
• a plurality of amplifiers respectively connected to said harmonic selectors for applying selected levels of positive or negative gain to modify each of said harmonic components;
• a summing device connected to said plurality of amplifiers for combining said modified harmonic components;
• and
• a digital-to-analog converter for re-synthesizing an analog output from said combined, modified harmonic components,
• wherein each said A/D converter, selector, amplifier and summing device is synchronized by a clock signal having a frequency which is a constant integer multiple of the fundamental frequency of said monophonic analog signal.

A method of modifying a monophonic analog signal having a fundamental frequency;

• the method comprising the steps of:
• digitizing said monophonic analog signal;
• splitting said digitized signal into its harmonic components;
• applying a selected level of positive or negative gain to each of said harmonic components;
• optionally shifting the frequencies of all components by a common factor;
• summing said modified harmonic components;
• converting said summed components into an analog signal;
• and
• controlling a clock signal to have a frequency which is a constant integer multiple of the fundamental frequency of said monophonic analog signal.