Digital receiver circuit
AssigneeNEC Corporation
InventorsTakeshi Nagahori, Shunichi Kanemitsu
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Abstract
A digital receiver circuit is easily integrated into a single chip. A differential output amplifier circuit is used for performing a binarizing decision by a quantizer for a differential output. A peak detection circuit, an average value detection circuit, an operational amplifier and a transistor are provided for controlling an input impedance and an offset of the differential output amplifier circuit depending upon a differential output. Thus, a capacitor for alternating current coupling as required conventionally, becomes unnecessary to facilitate integration into a single chip with minimum number of parts by full DC coupling.
Claims12
A digital receiver circuit including a photoelectric converter element for converting an input light into an electric signal, a differential output amplifier circuit receiving an output of said photoelectric converter element, a control circuit controlling an offset and an input impedance of said differential output amplifier circuit, and a quantizer for binarizing an output of said differential output amplifier, said control circuit further comprising:
- first and second peak detection circuits respectively detecting peak values of said differential output;
- a peak difference detection circuit for detecting a difference between two peak values detected by said first and second peak detection circuits;
- an offset control circuit for controlling the offset of said differential output amplification circuit depending upon a result of detection of said peak difference detection circuit;
- an average value detection circuit for deriving an average value of said two peak values detected by said first and second peak detection circuits;
- a comparator circuit for comparing derived average value with a predetermined reference voltage;
- and
- an input impedance control circuit for controlling an input impedance of said differential output amplification circuits depending upon a result of the comparison of said comparing circuit.
A digital receiver circuit including a photoelectric converter element for converting an input light into an electric signal, a transimpedance amplifier amplifying an output of said photoelectric converter element, a differential output amplifier circuit outputting a result of a comparison of an amplified output, a predetermined reference voltage as a differential signal, and a quantizer for binarizing the output of said differential output, said control circuit further comprising:
- first and second peak detection circuits respectively for detecting peak values of said differential output;
- a peak difference detection circuit for detecting a difference between two peak values detected by said first and second peak detection circuits;
- an offset control circuit for controlling the offset of said differential output amplifier circuit depending upon a result of detection of said peak difference detection circuit;
- a third peak detection circuit for detecting a peak value of an output of said transimpedance amplifier;
- and an input impedance control circuit for controlling an input impedance of said differential output amplification circuit depending upon a peak value detected by said third peak detection circuit.
Dependencies are inferred from the claim text.