Compandor system with stable and widely adjustable unity gain level
AssigneeNorth American Philips Corporation
InventorsNasrollah S. Navid, Michael J. DeLurio
Life of this patent
Estimating the term…
Abstract
A compandor system is provided that uses integrated circuitry in combination with fully external controlling devices for unity gain level adjustment without affecting the dynamic range. In addition, the system's stability is maintained. The external control is provided, for instance, by replaceable discrete resistors.
Claims18
An electronic compandor system having a signal input, a signal compressor coupled to the signal input, a signal expandor coupled to the compressor through a transmission channel and to a signal output, at least the compressor or the expandor comprising an integrated circuit that includes:
- first and second nodes;
- a voltage-to-current converter, adapted to be coupled to the first node through a first resistor for providing at a converter output a control current indicative of a signal voltage at the first node;
- a current multiplier, adapted to be coupled to the first node through a second resistor for receiving an input current, the multiplier being coupled to the converter for receiving the control current, wherein the multiplier supplies an output current at the second node substantially proportional to the input current and to the control current and substantially inversely proportional to a reference current;
- and wherein the integrated circuit comprises adjustment means for externally adjusting the reference current.
An integrated circuit including:
- a first node and a second node;
- a voltage-to-current converter adapted to be connected to the first node through a first resistor for providing at a control output a control current indicative of a voltage at the first node and inversely proportional to the first resistor;
- a current multiplier adapted to be coupled to the first node through a second resistor, for receiving an input current proportional to the voltage at the first node and inversely proportional to the second resistor, and coupled to the control output for receiving the control current, the multiplier supplying an output current to the second node substantially proportional to the input current and to the control current and substantially inversely proportional to a reference current;
- the integrated circuit further including adjustment means for externally adjusting the reference current.
Dependencies are inferred from the claim text.