Voltage controlled amplifier
OwnerPaul C. Buffinventor
Life of this patent
Estimating the term…
Abstract
A voltage controlled amplifier or multiplier circuit including a dual polarity rectifier for dividing the AC input signal into first and second unipolar signals, the first unipolar signal being the positive excursion of the AC input signal and the second unipolar signal being the inverted negative portion of the AC signal. Each unipolar signal is processed through a separate, conventional, unipolar log-antilog amplifier circuit, to each of which is applied a control voltage. The resultant unipolar signals are then subtracted in a differential amplifier to reconstitute the waveform of the original AC input signal, thereby producing the gain-controlled output signal.
Claims9
A voltage controlled amplifier apparatus comprising:
- (a) input means for dividing the positive and negative portions of the waveform of an A.C. input signal into first and second unipolar signals, respectively,
- (b) a first unipolar log amplifier circuit connected to said input means to receive only said first unipolar signal and to produce a first log signal logarithmically related to said first unipolar signal,
- (c) a second unipolar log amplifier circuit connected to said input means to receive only said second unipolar signal and to produce a second log signal logarithmically related to said second unipolar signal,
- (d) a first unipolar anti-log amplifier circuit having its input connected to the output of said first unipolar log amplifier circuit,
- (e) a second unipolar anti-log amplifier circuit having its input connected to the output of said second unipolar log amplifier circuit,
- (f) means for applying a gain control signal to both said first log signal and said second log signal to produce a first output signal at the output of said first unipolar anti-log amplifier circuit anti-logarithmically related to the sum of said gain control signal and said first log signal, and to produce a second output signal at the output of said second unipolar anti-log amplifier circuit anti-logarithmically related to the sum of said gain control signal and said second log signal, and
- (g) output means for combining said first and second output signals to produce a gain-controlled resultant signal reconstituting the original waveform of said input signal.
Dependencies are inferred from the claim text.