Compression/expansion techniques for time varying signals

Claim 2

A nonlinear signal translation circuit comprising: means for receiving signals; means for differentiating the received signals; nonlinear circuit means for instantaneous transformation of the amplitude of the differentiated signals to vary the amplitude thereof including bipolar AC log amplifier means for providing the log of the differentiated signals, said log amplifier means comprising a constant current source, matched diodes having a log characteristic connected in circuit with said constant current source, and means connected to said diodes for receiving the differentiated signals and operable in response thereto to maintain the connection point with said dIodes at zero volts DC; and means for integrating the transformed signals to obtain the same received waveform at a different amplitude.

Claim 3

The circuit according to claim 1, wherein the last-mentioned means includes a first amplifier connected between said differentiator means and said point, means for sensing the current at said point, means for comparing the sensed current to a reference including a second amplifier having a zero gain for alternating current coupled back to said point to effect AC signal generation.

Claim 4

The circuit according to claim 1, wherein said diodes comprise a diode bridge having first terminals connected in circuit with said constant current source and a second pair of terminals connecting said bridge across said point and a reference potential.

Claim 5

A nonlinear signal translation circuit comprising: means for receiving signals; means for differentiating the received signals; nonlinear circuit means for instantaneous transformation of the amplitude of the differentiated signals to vary the amplitude thereof including bipolar AC log amplifier means for providing the log of the differentiated signals, said log amplifier means comprising a constant current source, a plurality of matched nonlinear impedances having a log characteristic connected in circuit with said constant current source, and means connected to said nonlinear impedances for receiving the differentiated signals and operable in response thereto to maintain the connection point with said nonlinear impedances at zero volts DC; and means for integrating the transformed signals to obtain the same received waveform at a different amplitude.

Claim 6

A nonlinear signal translation circuit comprising: means for receiving signals; means for differentiating the received signals; nonlinear circuit means for instantaneous transformation of the amplitude of the differentiated signals to vary the amplitude thereof including bipolar AC log amplifier means for providing the log of the differentiated signals, said log amplifier means comprising a constant current source, a plurality of matched nonlinear impedances having a log characteristic connected in circuit with said constant current source, and means connected to said nonlinear impedances for receiving the differentiated signals and operable in response thereto to maintain the connection point with said nonlinear impedances at zero volts DC; and means for integrating the transformed signals to obtain the same received waveform at a different amplitude.

Claim 7

The circuit according to claim 4, wherein said means for receiving signals includes a buffer amplifier.

Claim 8

The circuit according to claim 4, wherein said differentiator means includes an operational amplifier, a capacitor coupled between said operational amplifier and said means for receiving signals and a feedback resistor connected across said operational amplifier and to said capacitor.

Claim 9

The circuit according to claim 4, wherein said means for integrating comprises an operational amplifier having a feedback capacitor connected thereacross, a resistor connected to said capacitor and to said operational amplifier, and an amplifier connected between said nonlinear means and said resistor.