Alps Electric Co., Ltd.

Satoshi Urabe

Sadao Igarashi

Kazuharu Aoki

Yoshio Saito

Jiro Kikuchi

Nobuyuki Suzuki

Yoshikiyo Watanabe

Since the transmit-receive unit of the prior art comprises the housing,made from a metal, the weight of the housing is large and the obtained transmit-receive unit for use in a portable telephone which is required to be light in weight becomes heavy. A transmit-receive unit comprises a housing which is made from a synthetic resin and has a conductive surface layer. Therefore, the housing is lighter in weight than a housing made from a metal of the prior art and makes it possible to provide a lightweight transmit-receive unit suitable for use in a portable telephone.

Transmit-receive unit

According to the present invention there is provided a transmitter-receiver unit for a portable telephone, comprising a transmission circuit block, a reception circuit block, an antenna terminal member with an antenna connected thereto for transmitting a transmission signal outputted from the transmission circuit block and for receiving a reception signal to be inputted to the reception circuit block, an antenna duplexer connected to the antenna terminal member, a printed wiring board having connectors and wiring patterns, the connectors having terminals connected to the transmission circuit block and the reception circuit block and also connected to the wiring patterns, and a frame for holding the printed wiring board, wherein the antenna terminal member is disposed at a corner position of one side of the printed wiring board, and the connectors are formed so that they each can be disposed at any of opposed positions on both sides of the printed wiring board.

Transmitter-receiver unit for portable telephone

According to the electronic device of the invention, the convex parts formed on the case is inserted into the engagement holes provided on the thermal conduction member, and the front ends of the convex parts are caulked to eliminate the plays. Further, the tongue-form pieces are formed on each of the two sides parallel to each other, the clasps are formed upright on the case, and the tongue-form pieces are hooked by the lower sides of the clasps. Further, the two sides where the tongue-form pieces of the thermal conduction member are formed are provided with slits that make it easy to deflect the tongue-form pieces, which facilitates the work to hook by slanting the upper sides of the clasps on the case, and further eliminates the plays.

Electronic device

An amplifier circuit comprises current-variable mode variable amplifying circuits and for amplifying an IF signal and a current-constant mode variable amplifying circuit for amplifying an RF signal. I and Q signals are applied to the IF-stage variable amplifying circuits and corresponding to two stages through a QPSK modulating circuit and amplified based on an AGC voltage VAGC applied thereto. The IF signal is converted into the RF signal by a mixer, which in turn is applied to the RF-stage variable amplifying circuit where it is amplified based on the AGC voltage VAGC common to the IF stages. The linearly-varied AGC voltage VAGC is converted into an exponentially-varied control current by transistors. Thus, a gain PG �dB! of each of variable amplifying circuits is controlled linearly with the AGC voltage VAGC.

Amplifier circuit having common AGC to IF and RF amplifiers for use in a

An object of the present invention is to provide an AGC voltage correction circuit unaffected by a change in temperature. Since base-emitter voltages V.sub.BE of transistors Q9 and Q10 constituting a first reference current source 7 have temperature dependency, the variations of the gains of amplification transistors Q17 and Q18 dependent on temperature are diminished. Since transistors Q1 and Q2 constituting a second reference current source 2 have temperature dependency, a gain slope concerning amplification transistors Q17 and Q18 relative to temperature is corrected linearly.

AGC voltage correction circuit

A multistage amplifier circuit comprises a current constant mode variable amplifying circuit for amplifying an input signal and current variable mode variable amplifying circuits and for further amplifying the signal amplified by the first variable amplifying circuit. An AGC voltage VAGC is commonly applied between the bases and emitters of an amplification degree control transistor of the current constant mode variable amplifying circuit and amplification degree control transistors of the current variable mode amplifying circuits. Collector currents of the transistors change exponentially with respect to the linearly-varied AGC voltage VAGC. Further, currents each proportional to the collector current of the transistor flow in the transistors. Thus, the gain PG �dB! of the current constant mode variable amplifying circuit changes linearly with the AGC voltage VAGC.

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Fukushima-ken, Japan

Satoshi Urabe