Fujitsu Ten Limited

Tatsuo Ito

Masataka Mizuno

Masakazu Moriyama

Toshitaka Yamato

Akira Motojima

Yuji Amaya

Shuji Sugawara

Shuji Nakane

Masahito Muto

Atsuyuki Takashima

Kazuyuki Hoda

A center loudspeaker is disposed near the middle between the left channel loudspeaker arranged at the front left side of the compartment and the right channel loudspeaker at the front right side, and this center loudspeaker transforms into a sound by the level-controlled signal of the sum of the acoustic signals of the right and left channels, and phase- and level-controlled signals of the acoustic signals of the right and left channels. As a result, the sound field is localized in the front of the listener, and right and left symmetrical wide-spread sound fields may be composed. Additionally, tweeters are disposed outside the right and left channel loudspeakers, and the mounting angles of the tweeters are adjusted so that the sounds released from the tweeters may be at an equal sound pressure level between the listener at the driver's seat and the listener at the front side seat. As a result, the drift of the sound field in the medium and high sound ranges may be eliminated in a simple structure, and right and left symmetrical wide-spread sound field are composed. Furthermore, corresponding to the opening or closing state of the window glass or seated position, by controlling the phase and level of the sounds released from the loudspeakers and the tweeters, sound fields always symmetrical to the listening position and spread widely may be composed.

Mobile acoustic reproducing apparatus

Delay circuit

An antenna for a vehicle-mounted receiver/transmitter includes: a driver for extending and retracting an antenna connected to the receiver/transmitter; a selector for selecting a frequency to be received and/or transmitted by the receiver/transmitter; and a controller which operates in response to an output from the frequency selector for causing the driver to extend and retract the antenna by the length corresponding to the frequency, and for retracting almost the entire antenna into the body of the vehicle when the receiver/transmitter is not operating.

Antenna apparatus for vehicle-mounted receiver/transmitter equipment

A radio receiver electronic tuning system includes a frequency sweep circuit for changing received frequencies by sequentially changing received frequency designating information, and a broadcasting wave search circuit for generating a search stop signal when receiving a broadcasting wave having a received electric field intensity higher than a certain level during the frequency sweep. The receiver further includes a preset channel selecting circuit for reading out the received frequency designating information prestored in a preset memory in an area corresponding to a channel selection key at the time of the operation thereof, thereby permitting direct channel selection. When an auto-preset key is actuated, the frequency sweep circuit is activated to sequentially change the received frequencies. When the search stop signal is generated during the sequential changing of the received frequencies, the received frequency designating information is stored in the preset memory.

Radio receiver of electronic tuning system having automatic presetting

An electronic tuning type radio receiver which is designed so that the received electric field intensity distribution in a received frequency band can be known at a glance. When predetermined key information is applied, receiving frequency designating information for determining the broadcasting station to be received is sequentially changed to detect the received electric field intensity of each received frequency. A received frequency vs electric field intensity distribution is produced based on the detected value and the corresponding received frequency and is displayed on a CRT display or the like.

Electronic tuning radio receiver

Manual channel selection apparatus

An electronic tuning radio receiver for executing digital channel selection is provided with a circuit means (b.sub.9) for detecting that a receiving frequency is out of the band and circuits (60, 62, 48, 50) for returning the receiving frequency within the band by the output of the above circuit means. Disadvantages that the receiving frequency is further driven below the lower limit of the band in the band switching can be avoided by these circuits. Pulse generator circuits (144, 142) are connected for the strobe terminals (G) of the multiplexer (46) switching various types of channel selection systems to moderate the channel selection speed by these circuits.

An AM/FM receiver provided with a frequency divider for frequency dividing the output frequency of a local oscillator to provide a count output which starts with '1' at the lower limit of a receiving frequency band and thereafter increases its count value for each constant frequency band (as the receiving frequency band is searched), a digital setter for setting a desired receiving frequency, and a comparator supplied with the outputs from the frequency divider and the digital setter to produce an output for gradually increasing or decreasing the output frequency of the local oscillator until the outputs from the frequency divider and the comparator come to coincide with each other. A desired broadcasting wave is automatically tuned with such a simple construction.

Radio receiver

A tuning control system of a radio receiver comprises a tuning voltage supply circuit which sweeps the received frequency by applying a variable control voltage to a variable reactance element of the tuning circuit and also stops the generation of the control voltage by means of a signal which is generated when a broadcasting signal is received. A memory for preset selection stores a counted value based on the received frequency signal and outputs this stored calculation value as a value corresponding to the desired broadcasting frequency. A digital comparator circuit compares the counted value based on the random receiving frequency signal and the counted output from the memory and generates a selection command signal for the tuning voltage circuit.

Tuning control system of radio receiver

A common indicator unit for a radio receiver and transceiver includes a segment type indicator consisting of a plurality of digits. An indication output corresponding to the receiving frequency of the radio receiver and an indication output corresponding to the channel of the transceiver are applied to the input terminal of the indicator after selection by switching.

Growing community of inventors

Kobe, Japan

Tatsuo Ito