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US 4,229,716 AGranted
Amplitude equalizer circuit
AssigneeNorthern Telecom Limited
InventorIsrael Levi
Life of this patent
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Abstract
An amplitude equalizer circuit utilizing active components in which unidirectional functional tuning of the amplitude, bandwidth and center frequency, may each be adjusted by varying a single resistance for each parameter. This eliminates the need for ganged-potentiometers or altering a plurality of interacting components.
Claims4
A variable amplitude equalizer circuit comprising:
- first and second operational amplifiers each having an inverting input, a non-inverting input and an output;
- a signal input and signal output coupled respectively to the inverting input and output of the first operational amplifier;
- a resistive divider network coupling the output of the first operational amplifier to the non-inverting input of the second operational amplifier;
- a first resistor connected in series between the output of the second amplifier and the non-inverting input of the first amplifier for controlling the amplitude of the equalizer circuit;
- a second resistor connected in shunt across the non-inverting input of the first amplifier to control the bandwidth of the equalizer circuit;
- a parallel resonant network connected in shunt across the non-inverting input of the first amplifier to control the center frequency of the equalizer circuit;
- whereby varying the parallel resonant network, the shunt connected resistor and the serially connected resistor in that order enables unidirectional functional tuning of the equalizer circuit.
4 more elements
Dependencies are inferred from the claim text.