Yokowo Co., Ltd.

Yuichi Kagoshima

Ryo Horie

Wasuke Yanagisawa

Takao Kawahara

Shozaburo Kameda

Tomio Anbe

Takumi Yano

Junichi Imai

Haruhisa Uchida

An antenna circuit which is improved the deterioration of amplitude characteristic in a strong electric field, an antenna circuit for AM broadcasting which can surely inhibit and damp FM-band signals in the strong electric field and amplifies to output AM-band signals, and an antenna circuit for AM/FM broadcasting in which AM-band signals are not damped by means of an FM-band filter. In the first antenna circuit, the output signal of an antenna ( ) is supplied to the base of a transistor Tr forming a current amplification type amplifier having a high-input and low-output impedance and the emitter of the transistor Tr is grounded through a coil L and connected to an FM receiver ( ) through a band-pass filter ( ). In the second antenna circuit for receiving AM broadcasting, an input terminal is connected to an AM amplifier circuit ( ) through coils (L ) and L in series and to the gate G of a field effect transistor FET. The source S of the transistor FET is grounded and the connecting point of the coils L and L is grounded through a capacitor C and a coil L in series. The second antenna circuit inhibits and damps FM-band signals in a plurality of steps. In the third antenna circuit for AM/FM broadcasting, the output signal of an antenna is divided into two parts and one part is supplied to an FM-band filter ( ) through a serial FM resonance circuit ( ) composed of capacitors and coils. The other part of the output signal is supplied to an AM-band filter ( ).

Antenna circuit

A motor-driven antenna device in which an antenna element (,) has a short protruding length so that the outer dimension of the entire device is reduced, and in which damping of an AM-band signal by a signal path is restrained with a small stray capacitance. A rack cord (,) to be meshed with a pinion gear (,) is connected to a proximal portion of the antenna element (,) made of a helical coil over its entire length, and the antenna element (,) is caused to protrude and move to be housed by rotational driving of a motor drive section. The rack cord (,), the motor drive section and the pinion gear (,) are housed in a case (,), and a guide (,) to which the rack cord (,) is abutted and moves while bending is provided in the case (,). Thus, the rack cord (,) is abutted and moves to the guide (,) by the movement of the antenna element (,). In a protruding state, a linear conductor (,) is extended from the proximal end of the antenna element (,) to penetrate an earth conductive fitting (,) and electrically connected with a connection conductive fitting (,) at a position not in contact with the earth conductive fitting (,). A feeder conductive fitting (,) elastically contacts and is electrically connected with the linear conductor (,).

Motor driven antenna apparatus

Growing community of inventors

Takasaki, Japan

Yuichi Kagoshima