Feedback amplifier distortion-cancelling circuit

Claim 2

A sound reproducing system comprising an amplifier for amplifying an input signal, a speaker driven by the output of said amplifier, and a differential amplifier for comparing a signal derived from said speaker containing a distortion component generated due to the non-linear characteristics of said speaker with another signal obtained in proportion to said input signal to extract oNly the distortion component, the output of said differential amplifier being coupled in opposite polarity to said amplifier, thereby eliminating the distortion component.

Claim 3

A sound reproducing system comprising a comparator for combining a distortion component in opposite polarity with an input signal, an amplifier for amplifying an output signal of said comparator, a speaker connected to the output terminal of said amplifier, an equalizer for equalizing the levels of said input signal to an output signal derived from said speaker at a reference frequency, and a differential amplifier for comparing the output signal of said speaker with the output signal of said equalizer to extract only said distortion component generated due to the non-linear characteristics of said amplifier and speaker.

Claim 4

A sound reproducing system comprising a comparator for combining a distortion component in opposite polarity with an input signal, an amplifier for amplifying an output signal of said comparator, a speaker connected to the output terminal of said amplifier, an equalizer for equalizing the levels of said input signal to an output signal derived from said speaker at a reference frequency, and a differential amplifier for comparing the output signal of said speaker with the output signal of said equalizer to extract only said distortion component generated due to the non-linear characteristics of said amplifier and speaker.

Claim 5

A sound reproducing system comprising a comparator for combining a distortion component in opposite polarity with an input signal, an amplifier for amplifying an output signal of said comparator, a speaker driven by the output of said amplifier, a detecting coil provided in said speaker and producing a voltage proportional to the speed of the cone paper of said speaker, an equalizer for equalizing the level and phase of said input signal to those of the signal generated from said detecting coil, and a differential amplifier for comparing said signal generated from said detecting coil with the output signal of said equalizer to extract only said distortion component included in said signal from said detecting coil.

Claim 6

A sound reproducing system comprising a comparator for combining a distortion component in opposite polarity with an input signal, an amplifier for amplifying an output signal of said comparator, a speaker driven by the output of said amplifier, a detecting coil provided in said speaker and producing a voltage proportional to the speed of the cone paper of said speaker, an equalizer for equalizing the level and phase of said input signal to those of the signal generated from said detecting coil, and a differential amplifier for comparing said signal generated from said detecting coil with the output signal of said equalizer to extract only said distortion component included in said signal from said detecting coil.

Claim 7

A sound reproducing system comprising a comparator for combining a motional distortion component in opposite polarity with an input signal, an amplifier for amplifying an output signal of said comparator, a motional component detecting bridge having one arm constituted by a speaker driven by the output of said amplifier, a motional detector connected to said motional component detecting bridge for detecting a distortion component from said speaker, a differential operator connected to said motional detector for producing an acceleration component signal, and a differential amplifier for comparing the output signal of said differential operator with said input signal to extract only said motional distortion component, the output of said differential amplifier being coupled in opposite polarity to said comparator.

Claim 8

A sound reproducing system comprising a comparator for combining a motional distortion component in opposite polarity with an input signal, an amplifier for amplifying an output signal of said comparator, a motional component detecting bridge having one arm constituted by a speaker driven by the output of said amplifier, a motional detector connected to said motional component detecting bridge for detecting a distortion component from said speaker, a differential operator connected to said motional detector for producing an acceleration component signal, and a differential amplifier for comparing the output signal of said differential operator with said input signal to extract only said motional distortion component, the output of said differential amplifier being coupled in opposite polarity to said comparator.

Claim 9

A sound reproducing system according to claim 4, which further comprises a phase shifter for shifting only the phase of said input signal, the phase-shifted output signal of said phase shifter being compared with the output signal of said differential operator in said differential amplifier to extract only said distortion component for coupling in opposite polarity to said comparator.

Claim 10

A sound reproducing system comprising a comparator for combining a distortion component in opposite polarity with an input signal, an amplifier for amplifying an output signal of said comparator, a speaker connected to the output terminal of said amplifier, a bridge detection circuit consisting of said speaker and resistors, a motional detector connected to said bridge detection circuit for generating an output signal including a motional component of said speaker and a voltage proportional to an electrical impedance of said speaker, a first equalizer for converting the output signal of said motional detector to the opposite polarity, a second equalizer for equalizing the level, phase and frequency of said input signal to those of the output signal of said first equalizer proportional to the motional component of the speaker and the electric impedance of the speaker, and a differential amplifier for comparing said output signal of said motional detector with said output signal of said second equalizer to extract only said distortion component generated due to non-linear characteristics of said speaker and said amplifier.

Claim 11

A sound reproducing system comprising a comparator for combining a distortion component in opposite polarity with an input signal, an amplifier for amplifying an output signal of said comparator, a speaker connected to the output terminal of said amplifier, a bridge detection circuit consisting of said speaker and resistors, a motional detector connected to said bridge detection circuit for generating an output signal including a motional component of said speaker and a voltage proportional to an electrical impedance of said speaker, a first equalizer for converting the output signal of said motional detector to the opposite polarity, a second equalizer for equalizing the level, phase and frequency of said input signal to those of the output signal of said first equalizer proportional to the motional component of the speaker and the electric impedance of the speaker, and a differential amplifier for comparing said output signal of said motional detector with said output signal of said second equalizer to extract only said distortion component generated due to non-linear characteristics of said speaker and said amplifier.

Claim 12

A sound reproducing system according to claim 1, which further comprises an equalizer for equalizing the level of said input signal to saId signal derived from said speaker at a reference frequency, the output of said equalizer being supplied to said differential amplifier.