Abstract: A radio broadcasting receiver having auto tuning process a digital signal processor includes a process for detecting a maximum value of a received signal output for each of a plurality of broadcasting stations selected during station selection, storage means for storing a detected maximum value of received signal output of each of the broadcasting stations, process for calculating a mean value of a plurality of stored maximum values of received signal outputs, and a process for calculating an output gain on the basis of a maximum value of a received signal output of a broadcasting station to be received and the mean value, and there is provided a process for conducting a gain control upon station selection according to an output of the digital signal processor so as to instantaneously bring the received signal output closer to the mean value, and which conducts automatically a sound volume adjustment at the time of station selection.

Abstract: A radio broadcasting receiver having an auto tuning means and a digital signal processor is disclosed, in which the digital signal processor includes a detection means for detecting a maximum value of a received signal output for each of a plurality of broadcasting stations selected during station selection, a storage means for storing a detected maximum value of received signal output of each of the broadcasting stations, a computation means for calculating a mean value of a plurality of stored maximum values of received signal outputs, and a means for calculating an output gain on the basis of a maximum value of a received signal output of a broadcasting station to be received and the mean value, and there is provided a means for conducting a gain control upon station selection according to an output of the digital signal processor so as to instantaneously bring the received signal output closer to the mean value, and which conducts automatically a sound volume adjustment at the time of station selection.

Abstract: A signal receiver that can function in any of three modes, such as normal mode, channel selecting mode, and mandatory announcement mode, is controlled by a microprocessor to mute the output signals or to release a muting operation depending upon the current mode. The signals being received contain an error detection/correction code and upon error decoding the number of error flags within predefined periods are checked to determine whether muting is required. The respective lengths of the predefined error flag checking periods are controlled in response to the current operating mode of the signal receiver.

Abstract: A system and method for providing service in a passenger vehicle having a plurality of passaenger seats. Tree-structured menu data are transmitted from a head end apparatus to a plurality of terminal units (each provided at one of the passenger seats) and the menu data are displayed at each terminal unit. Request signals indicating menu times selected by the passengers are returned to the head end apparatus, where they may be centrally processed and displayed, in order to provide improved service for the passengers.

Abstract: An information transmission system for transmitting signals from a transmitting side through a single transmission line to a plurality of terminal units. When the terminal units are interrupted by a command signal from the transmitting side, transmission of ordinary information signals to the terminal units is inhibited. When the terminal units are released from the interrupt mode, transmission of ordinary information signals automatically resumes, so that the ordinary information signals are reproduced from the point in time point at which they were interrupted. Normal operation of the terminal units is partially or totally inhibited during the interrupt mode. The system may be embodied in a passenger vehicle, in which a terminal unit is provided at each of a plurality of passenger seats.