Abstract: The present invention provides monitoring a sounding state of a speaker even in a case where any given sound is broadcast. In detecting the sounding state of the speaker with the microphone for sound detection, noises around the speaker are also collected by the microphone for sound detection. Therefore, in a case where there are ambient noises, it is difficult to monitor the sounding state of the speaker.

Abstract: The present invention provides monitoring a sounding state of a speaker even in a case where any given sound is broadcast. In detecting the sounding state of the speaker with the microphone for sound detection, noises around the speaker are also collected by the microphone for sound detection. Therefore, in a case where there are ambient noises, it is difficult to monitor the sounding state of the speaker.

Abstract: A wireless device capable of reliably detecting a tone squelch signal in a short time is provided. The wireless device which detects a tone squelch signal contained in received baseband signals is provided with: a frequency shifting unit (quadrature demodulation unit (503)) which shifts the received baseband signal in the negative frequency direction by a preset frequency of a tone squelch signal; LPF (504-1, 504-2) for eliminating unnecessary frequency components from the output of the frequency shifting unit; and an assessment unit (510) which assesses presence/non-presence of the tone squelch signal on the basis of the output from the LPF (504-1,504-2).

Abstract: A wireless device capable of reliably detecting a tone squelch signal in a short time is provided. The wireless device which detects a tone squelch signal contained in received baseband signals is provided with: a frequency shifting unit (quadrature demodulation unit (503)) which shifts the received baseband signal in the negative frequency direction by a preset frequency of a tone squelch signal; LPF (504-1, 504-2) for eliminating unnecessary frequency components from the output of the frequency shifting unit; and an assessment unit (510) which assesses presence/non-presence of the tone squelch signal on the basis of the output from the LPF (504-1,504-2).

Abstract: Forward and backward equalization processes are effectively used in a communication system for equalizing a received signal of a frame including a known symbol part. The known symbol part is provided in a position other than both ends of the frame. An equalization filter unit acquires a signal of an equalization process result by performing an equalization filter process based on a signal serving as an equalization process target and a tap gain coefficient. An update unit updates the tap gain coefficient using a predefined algorithm. A first or second transmission unit transmits a received signal posterior or prior to the known symbol part to a first or second memory in a forward direction or reverse order.

Abstract: An inter-base station synchronization system is constructed without using any receiver for detecting a frame period error at a zone boundary between leaky coaxial cables, and without using any exclusive line or dedicated radio waves for use in transmitting the frame period error information from this receiver to base stations. This system has a plurality of base stations provided in certain intervals, leaky coaxial cables laid down between the base stations, and one, or a plurality of, mobile station that measure a time delay difference of received signals from adjacent ones of the base stations while the mobile stations move along zone boundaries between leaky coaxial cables, and that transmit the delay time difference information through the leaky coaxial cables to at least either one of the two adjacent base stations.

Abstract: A method for use in an apparatus for frequency error detection and automatic frequency control detects a frequency error by utilizing known symbols other than a data signal contained in an input signal. At least two known symbols located at positions somewhat distant from each other in the input signal are extracted therefrom. A phase shift between the two known symbols in the input signal represents a frequency shift of the input signal. The frequency shift of the input signal is detected from the phase shift. A first symbol set including at least two known different symbols and a second symbol set including at least two known symbols having a different symbol distance from that of the first symbol set are extracted.

Abstract: Forward and backward equalization processes are effectively used in a communication system for equalizing a received signal of a frame including a known symbol part. The known symbol part is provided in a position other than both ends of the frame. An equalization filter unit acquires a signal of an equalization process result by performing an equalization filter process based on a signal serving as an equalization process target and a tap gain coefficient. An update unit updates the tap gain coefficient using a predefined algorithm. A first or second transmission unit transmits a received signal posterior or prior to the known symbol part to a first or second memory in a forward direction or reverse order.

Abstract: A gain of an amplifier of a receiver is automatically controlled based on a level of a signal received by the receiver. The instantaneous value of the envelope of the received signal is detected sequentially at predetermined time intervals. The first interval average value providing an average of the instantaneous value for a first predetermined time length, and the second interval average value providing an average of the instantaneous value for a second predetermined time length are determined. The difference between the instantaneous value and the first interval average value is determined. When the difference exceeds a predetermined threshold value, the gain of the amplifier corresponding to the second interval average value is set after a predetermined third time length.

Abstract: An inter-base station synchronization system is constructed without using any receiver for detecting a frame period error at a zone boundary between leaky coaxial cables, and without using any exclusive line or dedicated radio waves for use in transmitting the frame period error information from this receiver to base stations. This system has a plurality of base stations provided in certain intervals, leaky coaxial cables laid down between the base stations, and one, or a plurality of, mobile station that measure a time delay difference of received signals from adjacent ones of the base stations while the mobile stations move along zone boundaries between leaky coaxial cables, and that transmit the delay time difference information through the leaky coaxial cables to at least either one of the two adjacent base stations.

Abstract: A method for use in an apparatus for frequency error detection and automatic frequency control detects a frequency error by utilizing known symbols other than a data signal contained in an input signal. At least two known symbols located at positions somewhat distant from each other in the input signal are extracted therefrom. A phase shift between the two known symbols in the input signal represents a frequency shift of the input signal. The frequency shift of the input signal is detected from the phase shift. A first symbol set including at least two known different symbols and a second symbol set including at least two known symbols having a different symbol distance from that of the first symbol set are extracted.

Abstract: A gain of an amplifier of said receiver is automatically changed in accordance with a level of a signal received by the digital radio receiver thereby to control a gain, wherein the instantaneous value of the envelope of the input received signal is detected sequentially at predetermined time intervals; the first interval average value providing an average of the instantaneous value for a first predetermined time length, and the second interval average value providing an average of the instantaneous value for a second predetermined time length are determined; the difference between the instantaneous value and said first interval average value is determined; and in the case where the difference exceeds a predetermined threshold value, the gain of the amplifier corresponding to the second interval average value is set after a predetermined third time length from said case occurred.