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US 3,940,681 AGranted
Wide amplitude range detecting circuit
AssigneeSony Corporation
InventorMitsuo Ohsawa
Life of this patent
Estimating the term…
Abstract
A detecting circuit with improved linearity of operation for small signal voltages. A rectifying transistor has switching means connected between its collector and base to be conductive when a signal voltage of one polarity is applied to the input circuit of the transistor and nonconductive when a signal voltage of the opposite polarity is applied. The rectified signal can be obtained from either the collector or emitter of the transistor.
Claims10
A detecting circuit comprising:
- A. a rectifying transistor comprising a base, an emitter, and collector, said base and emitter comprising components of a base-emitter input circuit to receive an input signal to be rectified, and said collector and said emitter comprising parts of an output circuit;
- B. zener diode switching means connected directly in series between said collector and said base, and controlled by said input signal to be conductive when said input signal has a polarity that tends to make said transistor conductive and to be non-conductive when said input signal has the opposite polarity;
- and
- C. an output terminal connected to said output circuit to derive therefrom a rectified signal corresponding to said input signal.
1 more element
The combination comprising:
- A. a detecting circuit comprising:
- (1) a rectifying transistor comprising a base, an emitter, and collector, said base and emitter comprising components of an input circuit to receive an input signal to be rectified, and said collector and said emitter comprising parts of an output circuit, and
- (2) switching means connected between said collector and said base, and controlled by said input signal to have a first conductivity condition when said input signal has one polarity and to have the opposite conductivity condition when said input signal has the opposite polarity;
- B. a second transistor, the gain of which is to be controlled;
- C. a third transistor, the base of said third transistor being connected to the emitter of said rectifying transistor to be receive a rectified signal therefrom, the emitter and collector of said third transistor comprising first and second rectified signal output terminals;
- D. a voltage divider comprising first and second impedances connected to one of said rectified signal output terminals to be energized thereby, the base of said second transistor being connected to the juncture between said first and second impedances and being connected to a high frequency signal source, said second impedance being controllable by a control voltage;
- and
- E. a connection between the other of said rectified signal output terminals and said variable impedance to control the magnitude thereof, whereby the gain of said second transistor is controlled by the magnitude of the voltage applied across said voltage divider and is inversely controlled by the magnitude of the voltage controlling said controllable impedance.
5 more elements
Dependencies are inferred from the claim text.