US 4,902,983 AGranted

Nonlinear signal generating circuit and nonlinear compensating device using the same

AssigneesNEC Corporation, Nippon Telegraph and Telephone Corporation

InventorsYoshinori Fujiki, Masatoshi Ishida, Nobuaki Imai, Toshio Nojima

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Abstract

A device for compensating for nonlinearity of amplifiers by use of a predistortion principle, and a nonlinear signal generating circuit built in such a device. The nonlinear signal generating circuit includes a quadrature hybrid of the type using a distributed constant line. Two diodes and a terminal resistor are connected in parallel and opposite in polarity to each other and connected between the terminals of coupling and passing ports of the hybrid and ground. The nonlinear compensating device is constituted by the combination of a plurality of quadrature hybrids of the type using a distributed constant line and various kinds of diodes. All the circuit segments of the device are implemented with a planar circuit provided on a single dielectric substrate and diodes which are held in a pair chip condition. Such circuitry is accommodated in a single air-tight housing to complete a microwave integrated circuit.

Claims11

Dependent claims

A nonlinear signal generating circuit comprising:

a quadrature hybrid having an input port, a coupling port, a passing port and an output port;
a first parallel connection constituted by a first and a second diode which are connected in parallel and opposite in polarity to each other and a first terminating resistor which is connected in parallel with said first and second diodes, said first parallel connection being connected at one end to said coupling port of said quadrature hybrid and at the other end to ground;
and
a second parallel connection constituted by a third and a fourth diode which are connected in parallel and opposite in polarity to each other and a second terminating resistor which is connected in parallel with said third and fourth diodes, said second parallel connection being connected at one end to said passing port of said quadrature hybrid and at the other end to ground, wherein said first diode of said first parallel connection and said third diode of said second parallel connection are connected to be identical in polarity, said second diode and said fourth diode are connected to be identical in polarity, and wherein first, second, third and fourth capacitors are connected between said first terminating resistor and ground, between said second diode and ground, between said second terminating resistor and ground, and between said fourth diode and ground, respectively.

1 more element

Dependencies are inferred from the claim text.