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US 4,491,800 AGranted
Switching circuit operable as an amplifier and a muting circuit
AssigneeNEC Corporation
InventorShinji Miyata
Life of this patent
Estimating the term…
Abstract
A switching circuit for achieving the amplifying and muting operations is disclosed. The switching circuit operates as a non-inverting feedback amplifier whenever the circuit performs either amplification or muting. The non-inverting input port of the amplifier is always kept free to receive a given signal. An impedance element is connected to the output terminal of the circuit in either the amplifying or muting operation.
Claims9
A switching circuit comprising:
- a signal input terminal;
- a signal output terminal;
- a reference potential terminal;
- an amplifier having an inverting input port, a non-inverting input port and an output port, and non-inverting input port being coupled to said signal input terminal;
- a first impedance element connected between said inverting input port and said reference terminal;
- a second impedance element and a third impedance element connected at their one ends to said inverting input port;
- and
- switching means for establishing connection relations among said output port, said signal output terminal, the other end of said second impedance element and the other end of said third impedance element;
- wherein said switching means performs the switching operation between a first state in which, while said other end of one of said second and third impedance elements is coupled to said output port, said other end of the other of said second and third impedance elements is coupled to said signal output terminal, and a second state in which said other end of one of said second and third impedance elements is coupled to said output port and said signal output terminal.
6 more elements
A circuit operable as an amplifier and a muting circuit comprising;
- an input terminal;
- an output terminal;
- a reference terminal;
- an amplifier having a non-inverting input port, an inverting input port and an output port, said non-inverting input port being coupled to said input terminal;
- a first resistor coupled between said inverting input port and said reference terminal;
- a second resistor having one end connected with said inverting input port;
- a third resistor having one end connected with said inverting input port and the other end coupled to said output terminal;
- a first switch inserted between the other end of said second resistor and said output port;
- a second switch inserted between the other end of said third resistor and said output port;
- and
- means for controlling said first and second switches so that only one of them is conductive at a time.
8 more elements
A circuit operable as an amplifier and a muting circuit comprising:
- an input terminal;
- an output terminal;
- a reference terminal;
- an amplifier having a non-inverting input port, an inverting input port and an output port, said non-inverting input port being coupled to said input terminal;
- a first resistor coupled between said inverting input port and said reference terminal;
- a second resistor having one end connected with said inverting input port and the other end connected with said output port;
- a third resistor having one end connected with said inverting input port;
- a first switch inserted between the other end of said second resistor and said output terminal;
- a second switch inserted between the other end of said third resistor and said output terminal;
- and
- means for controlling said first and second switches so that only one of them is conductive at a time.
8 more elements
Dependencies are inferred from the claim text.