Matsushita Electric Industrial Co., Ltd.

Yoshikazu Mori

Morikazu Sagawa

Mitsuo Makimoto

Sadahiko Yamashita

Motoi Ohba

Kazuaki Takahashi

Keiichirou Kuwaduru

A frequency converter may be employed in communication equipment such as a portable telephone. The frequency converter includes a differential pair consisting of first and second transistors, a current bypass circuit consisting of third and fourth transistors, and a distortion compensating circuit consisting of fifth and sixth transistors. The distortion compensating circuit decreases an emitter-to-base voltage of the sixth transistor when an emitter current of the first transistor is increased, while it increases an emitter-to-base voltage of the fifth transistor when an emitter current of the second transistor is decreased, non-linearts components of the emitter-to-base voltages of the first and second transistors caused by variations of RF (radio-frequency) signals inputted to the first and second transistors are called decreasing distortion of an output signal of the frequency converter caused by the difference in operating point between the first and second transistors.

Frequency converter apparatus with distortion compensating circuit

A wide band analog frequency divider circuit operable at a high frequency in the GHz band, and a frequency synthesizer utilizing the analog frequency divider circuit. The analog frequency divider circuit comprises an LC series circuit having a capacitor and an inductor connected between the anode and the cathode of a diode, and means for applying a forward bias to the diode. The input signal is supplied from the anode side of the diode, and the output is delivered from the cathode side, or the anode side of the cathode is grounded. The frequency synthesizer is arranged to frequency divide the output of a VCO by the analog frequency divider circuit, and to supply the frequency-divided output to a prescaler. The output of the prescaler is further frequency divided by a programmable divider, and the phase difference between the output of the programmable divider and a reference signal is detected thereby to control the oscillation frequency of the VCO.

Frequency divider circuit and frequency synthesizer using the same

A wide band analog frequency divider circuit operable at a high frequency in the GHz band. The analog frequency divider circuit comprises an LC series circuit having a capacitor and an inductor connected between the anode and the cathode of a diode, and means for applying a forward bias to the diode. The input signal is supplied from the anode side of the diode, and the output is delivered from the cathode side, or the anode side if the cathode is grounded.

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Kawasaki, Japan

Yoshikazu Mori