Matsushita Electric Industrial Co., Ltd.

Mikio Hanabusa

Kazunori Watanabe

Kaoru Ishida

Kouichi Kunitomo

Masaki Suzuka

A receiving device includes a receiver circuit for outputting a received signal as a reception electric field intensity signal, an operation control circuit for controlling an operation of the receiver circuit, and an intermittent reception control circuit for outputting a periodic signal. A comparator circuit holds a first threshold indicating that the receiving device has entered a communication area and a second threshold indicating a start of a continuous electric field intensity measurement. If the reception electric field intensity signal is lower than the second threshold, the operation control circuit makes the receiver circuit perform intermittent operation. If the reception electric field intensity signal is equal to or higher than the second threshold, the operation control circuit makes the receiver circuit perform a continuous operation. If the reception electric field intensity signal is equal to or higher than the first threshold, the operation control circuit makes the demodulation circuit perform an operation.

Receiving device, semiconductor integrated circuit, transmitting/receiving device, transport apparatus portable transmitting/receiving device, communication system and receiving method

A transmission power control method includes a step (a) of receiving by a receiver a radio wave signal, a step (b) of judging whether a first identification signal is included in the received radio wave signal, a step (c) of detecting a reception electric field intensity of the radio wave signal included in the radio wave signal in the case where the first identification signal is included in the radio wave signal, a step (d) of obtaining a radio wave propagation state between a home station and the station to communicate with by using the reception electric field intensity detected at the step (c) and determining transmission power of the transmission radio wave signal based upon the radio wave propagation state, a step (g) of invalidating the radio wave propagation state obtained upon the previous reception in the case where the interval between an end of communication and a restart of communication is longer than a time determined in advance, a step (e) of superimposing a second identification signal on the transmission radio wave signal and a step (f) of controlling such that the transmission power of the transmission radio wave signal becomes the value determined at the step (d).

FM radio device and transmission power control method

A modulation sensitivity correction circuit in which a phase-locked loop includes a voltage-controlled oscillator (VCO) and a phase detector. When an audio signal is applied to the VCO through an electronic volume control so as to be modulated, control for the electronic volume control is effected by using a control voltage obtained by applying an output of the phase detector to a conversion circuit having a characteristic which is the reverse of the modulation sensitivity characteristic of the VCO, so that the modulation sensitivity can be kept constant over a wide band.

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Kanagawa, Japan

Mikio Hanabusa