Pioneer Electronic Corporation

Pioneer Electric Corporation

Shintaro Gomi

Katsuaki Kawamura

Masashi Shimakata

Junichi Shibata

Yasuhiro Oshime

Shigeki Takeda

Tomohisa Yokogawa

Haruyuki Inohana

Tomoshisa Yokogawa

A differential amplifier comprises: first and second transistors the emitters of which are connected to each other through a resistance element; a third transistor to the emitter of which a current equal to the collector current of the first transistor is applied; and a fourth transistor to the emitter of which a current equal to the collector current of the second transistor is applied. Signals provided at the emitters of the third and fourth transistors, after being level-shifted, are supplied to the bases of the second and first transistors, respectively. Thereby, a differential amplifier which is linear in transfer characteristic and large in input dynamic range is obtained.

Differential amplifier

A mobile antenna unit for use in the FM broadcast band which is adapted to be mounted on the windshield of the vehicle and which provides a gain and directivity pattern similar to those of an external whip antenna. The antenna element takes the form of a conductor mounted near one of the pillars supporting the windshield. The pillar appears electrically as an inductor and the conductor as a capacitor. By properly dimensioning and spacing the conductor with respect to the pillar, resonance is achieved in the FM broadcast band.

Mobile antenna unit

A complex antenna system including at least two loop antennas crossing each other and connected with each other at the electric neutral points thereof, and a rod antenna positioned at the central portion of the loop antennas. An FM and/or AM tuners combined with the complex antenna system utilizes selected one of the loop antennas for receiving an FM wave so as to avoid multi-path noises.

Complex antenna system and FM/AM receiver

An antenna array system which comprises at least one balanced antenna having an electric neutral point and two output end terminals positioned closely to each other, at least one unbalanced antenna having one end thereof dc-coupled with the electric neutral point of the balance antenna and the other end thereof positioned closely to the end terminals of the balanced antenna, first means for picking up a first frequency wave signal such as FM wave signal from the balanced antenna, and second means for picking up a second frequency wave signal such as an AM wave signal from the unbalanced antenna.

Antenna array system usable for AM/FM receiver

An input signal level control device for a receiver particularly adapted for use in a mobile FM receiver in which the received electric field strength changes abruptly and greatly. An attenuating device such as a switching diode is coupled to an input of a high frequency amplifier to which the input received signal is fed. The attenuating device switches on when the received electric field strength reaches the first predetermined value. As the electric field strength continues to increase and reaches a second value greater than the first, a control circuit controls the gain of the high frequency amplifier in accordance with the electric field strength.

Input signal level control device for receiver

An FM receiver provided with an array of antennas and suitable for use in a moving vehicle such as a motorcar, which is provided with means for automatically avoiding multipath noises. The means so operates as to connect one of the antennas in an instantaneously best sensing condition to an FM tuner.

Growing community of inventors

Saitama, Japan

Shintaro Gomi