Nec Corporation

Nippon Electric Co., Ltd.

Calsonic Corporation

Koji Iwahashi

Fumio Hagi

Takenosuke Sano

Masahiro Honma

Yukihiro Niide

A baseband signal processing circuit for a radio communication apparatus has an amplifier for amplifying the amplitude of an input baseband signal, a limiter for limiting the amplitude of the amplified baseband signal, an amplitude detector for detecting the amplitude of the output signal of the amplifier, and a control unit for controlling the gain of the amplifier in response to the output of the amplitude detector. When the amplitude detector detects an amplitude greater than a predetermined level, the control unit controls the gain of the amplifier in such a manner as to maintain the output of the amplifier at a constant level. As a result, the output level of the amplifier is prevented from exceeding the limiter level of the limiter. This allows the maximum frequency transition to be set up with no regard to frequency and suppresses distortions regarding signals exceeding the standard frequency transition.

Baseband signal processing circuit for a radio communication apparatus

A radio communication apparatus includes a transmitting portion supplied with input baseband signals for selectively transmitting the input baseband signals in response to a selection signal. The transmitting portion includes a selector for selecting one of the input baseband signals as a selected baseband signal in response to the selection signal. A level controller has a controllable gain and controls the selected baseband signal so that the selected baseband signal has a level which is determined by the controllable gain. A gain controller has predetermined gains in correspondence to the input baseband signals and controls the controllable gain in response to the selection signal so that the controllable gain becomes equal to one of the predetermined gains that corresponds to the selected baseband signal. A converter converts the selected baseband signal into a radio signal carrying the selected baseband signal. The gain controller may have a memory for memorizing the predetermined gains. Responsive to the selection signal, a reading circuit reads from the memory, as a read-out gain, one of the predetermined gains that corresponds to the selected baseband signal. A control circuit controls the controllable gain so that the controllable gain becomes equal to the read-out gain.

Radio communication apparatus comprising a single level controller

An alcohol concentration detecting device is disclosed, which comprises an alcohol sensor of capacitance type having a probe portion which is to be submerged in an alcohol-mixed fuel, the alcohol sensor issuing an output signal which varies in accordance with the concentration of alcohol in the alcohol-mixed fuel; a first oscillating circuit which receives the output signal of the alcohol sensor and issues a variable pulse signal whose duty ratio is variable in accordance with the output signal; a second oscillating circuit which issues a reference pulse signal, the reference pulse signal being the same as the pulse signal which is provided by the first oscillating circuit when there is no alcohol in the fuel; and an alcohol concentration detecting circuit which receives and compares the variable pulse signal and the reference pulse signal and issues an alcohol concentration representing signal which is variable in accordance with a difference in duty ratio between the variable pulse signal and the reference pulse signal.

Alcohol concentration detecting device

A battery charger for a vehicle-mounted equipment comprises a first sensor for detecting when the voltage of the vehicle battery is higher than a specified level. A second sensor is provided for detecting when the engine of the vehicle is running. The outputs of the sensors determine the start timing of a charging operation. A switch is connected between the vehicle battery and the equipment's rechargeable battery. A timing circuit is responsive to the output signals of the first and second sensors for causing the switch to establish a path between the batteries for an interval sufficient to charge the rechargeable battery with a current supplied from the vehicle battery.

Battery charger for vehicle-mounted equipment using engine operation as

A radio reciever having a plurality of intermediate frequency amplifiers and a field intensity detector. A control circuit is provided which generates a control signal for reducing the gains of the intermediate frequency amplifiers in response to an output of the field intensity detector and when a voltage associated with an input field intensity has risen beyond a predetermined level.

Radio receiver with field intensity detector

A receiver utilizing a switched capacitor filter is disclosed. The switched capacitor filter has a band pass determined by a control signal applied thereto. A waveform shaping circuit generates the control signal as a function of a received signal which has been modulated in angle and amplified. The wave shaper generates the control signal only when the amplified signal is above a predetermined value and generates the signal at a frequency which causes the switched capacitor filter to operate at the correct band pass.

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Tokyo, Japan

Koji Iwahashi