Sony Corporation

Nobutaka Takao

Satoshi Yokoya

Hiroshi Yasuda

Kotaro Takagi

Takayuki Inoue

Noboru Someno

Akira Todo

A radio transmitter apparatus arranged such that transmission efficiency is improved by switching the load impedance on the final stage in response to the power source voltage or the transmission output power.

Radio transmitter apparatus which optimizes load impedance to maximize

A power control circuit for use in radio transmitters such as portable telephone sets includes a power amplifier for amplifying the power of a transmission signal to obtain an output signal; control circuits for controlling the amplitude of the signal output by the power amplifier; a limiter for partially limiting the amplitude of the signal from the power amplifier in order to obtain a limited signal; a multiplication circuit for multiplying the limited signal from the limiter and part of the signal from the power amplifier in order to acquire a multiplied signal; a low-pass filter for extracting a DC component of the multiplied signal from the multiplication circuit; and a comparison circuit for comparing the DC component from the low-pass filter with a reference voltage in order to obtain a comparison output. The comparison output from the comparison circuit is supplied to the control circuits, and the control circuits control the level of the signal from the power amplifier so that the DC component from the low-pass filter will become equal to the reference voltage regardless of temperature change.

Power control circuit

A radio communication apparatus comprising a modulating portion for modulating a carrier with a signal to transmit so as to produce a transmissible signal; a signal transmitting portion for transmitting the transmissible signal; a level adjusting portion for adjusting a level of the signal to transmit or a level of a control signal used for controlling the transmissible signal in accordance with digital control data supplied to the level adjusting portions; a memory for storing digital adjusting data; and a control unit for reading the digital adjusting data from the memory and supplying the level adjusting portion with the digital adjusting data read from the memory or modified digital adjusting data obtained based on the digital adjusting data read from the memory as the digital control data.

Radio communication apparatus with programmable signal modulation

A filter apparatus comprised of a multi-layer printed circuit board has a shielded filter with input and output terminals protruding from the circuit board, when the filter is mounted on the printed circuit board. Two insulating substrates form the printed circuit board, and a connective conductive pattern is formed on an inner surface of one of the substrates that faces the other substrate. Conductive layers are formed on respective outer surfaces of the substrate opposing the connection conductive pattern, wherein at least one of the input and output terminals of the filter is connected to the connective conductive pattern and the conductive layers are grounded, thereby shielding the connective conductive pattern.

Filter apparatus

A radiotelephone apparatus employed as a so-called portable telephone or a car telephone includes an outer casing, a chassis base plate provided in the outer casing and mounting an electronic circuit section containing above all a heated element or elements, and a fan containing section containing a heat sink and a fan device connected in a heat conductive relation with the chassis base plate. The electronic circuit section and the fan containing section within the outer casing are isolated from each other by an air current interrupting device for air cooling heated electronic components while preventing dust and dirt in the air from flowing into portions in the casing other than the fan containing section. An air intake window is provided in the vicinity of mechanically operating portion of the apparatus for self cleaning dust and dirt sucked by the air flow through the normal telephone operation.

Radiotelephone apparatus

A radio communication apparatus has a modulating portion for modulating a carrier with a signal to be transmitting so as to produce a transmission signal. A signal transmitting portion causes the transmissible signal to be subjected to power amplification. The transmissible signal is transmitted after having been subjected to power amplification. A cooling device is provided for cooling by force a heat source contained in the signal transmitting portion in response to a condition detector for detecting a temperature condition or an operating condition of the signal transmitting portion. An operation control unit is operative to cause the cooling device to be in operation when a particular temperature condition in which temperature of the signal transmitting portion has exceeded a predetermined value or a particular operating condition in which the signal transmitting portion has been in a predetermined state is detected by the condition dectector.

Growing community of inventors

Kanagawa, Japan

Nobutaka Takao