Abstract: A method of selecting one of broadcast waves, which are received by a receiving system for receiving the broadcast waves in each of which a sub signal including input sorting information to indicate a sort of broadcast for each of the broadcast waves is multiplexed a main signal, includes the steps of: setting a set sorting information to specify a desired sort of broadcast to be received; judging whether or not the input sorting information of each of the received broadcast waves is coincident with the set sorting information; storing the input sorting information if the input sorting information is not judged to be coincident by the judging step; firstly selecting one of the broadcast waves having the input sorting information, which is judged to be coincident by the judging step, if at least one of the input sorting information is judged to be coincident by the judging step; and secondly selecting one of the broadcast waves having the input sorting information, which is not judged to be coincident by the j

Abstract: A program type code (PTY) burst signal detection method for a radio data system (RDS) receiver, which can automatically receive an arbitrary information program from another network from the beginning of the program. This detection method detects a PTY burst signal in RDS data, which is indicative of switching of broadcasting of an information program from another network. The PTY burst signal is defined as a signal obtained by transmitting RDS data of a group type 14A comprising an information classification code (Usage Code)=(13) in a second block several times in a short period of time. This detection method respectively compares data of three blocks at least in the 14A group, excluding the first block thereof, with data of the three blocks received earlier, and detects the PTY burst signal when every compared data matches with associated data by a predetermined number of times.

Abstract: A noise reducing circuit for a receiver such as an FM receiver which is improved in noise reducing effect while reducing an unfamiliar feeling to and an erroneous operation of the receiver. The noise reducing circuit comprises fuzzy inference means for fuzzy inferring, using an input vector consisting of several factors defining a receiving input condition as a prerequisite, in accordance with fuzzy production rules provided by membership functions of the factors of the input vector, and a fuzzy controlling signal generating circuit for generating a fuzzy controlling signal for controlling a control object amount of any one of a separation control circuit, a frequency characteristic control circuit and muting circuit or each of any combination of the circuits in accordance with a result of inference produced by the fuzzy inference means.

Abstract: A radio receiver is disclosed having a wide filter and a narrow filter, each of which is connected with the front end and outputs an intermediate frequency signal. To the output of the filters are connected first and second detectors, respectively. A subtracter receives the outputs of the detectors and subtracts one from the other. A switch receives the output of the subtracter and directs the outputs of detectors in such a way that the switch is switched to a first position for directing the demodulated output from the first detector to a following circuit when the difference is below a reference level, and to a second position for directing the demodulated output from the second detector to the following circuit when the difference is above the reference level.

Abstract: A noise reducing circuit for reducing various noise in the output of a receiver. A noise attenuating circuit receives a demodulated signal and attenuates the noise in the demodulated signal in accordance with a control signal supplied thereto. A signal strength detecting circuit outputs a field intensity signal indicative of a strength of a radio wave signal inputted to the receiver. An output noise level detecting circuit outputs a noise level signal indicative of a noise level in the demodulated signal after the noise is attenuated. A fuzzy inferring circuit performs fuzzy inference in accordance with fuzzy production rules given by membership functions for the field intensity signal and the noise level signal, respectively so as to output an inference output. A control signal generating circuit produces the control signal on the basis of the inference output to control the noise attenuating circuit.

Abstract: A diversity receiver has distributors each of which is connected with each of a plurality of antennas, and as many antenna switches as there are receivers. Each of the antenna switches has as many contacts as there are distributors. The distributor distributes a radio frequency signal from the antenna into as many signal paths as there are receivers. Each of the antenna switches is connected with each of the distributors via the contact connected with the signal path. A demodulated signal selecting circuit has as many contacts as there are said receivers. The demodulated signal selecting circuit receives the demodulated output of the receivers via each of said second contacts to selectively output the demodulated outputs of the receivers.

Abstract: A reception sensitivity control system in a sweeping receiver in which a frequency dividing ratio of a phase lock loop is instantly changed from one end of the band to the other. The number of receivable stations is counted in the period of time required for the phase lock loop to adjust. If the number of stations is less than a preset minimum, the input sensitivity is increased. Thereafter, the channels are selected.