A diversity receiver includes first and second receivers, a first switch, a comparator, a second switch, and a controller. The first and second receiver have receiver antennas and generate demodulated signals and electric field detection outputs in accordance with received electric fields, respectively. The first switch performs switching between the demodulated signals from the first and second receivers in accordance with an output switching control signal and outputs a selected demodulated signal. The comparator compares the electric field detection outputs from the first and second receivers, respectively, and supplies the output switching control signal to the first switch. The second switch turns on/off a power source of the first receiver in accordance with a power source switching control signal. The controller receives the electric field detection output from the second receiver, calculates an average intensity of the electric field, and supplies the power source switching control signal to the second switch in accordance with the average intensity of the electric field.
A simultaneous broadcasting receiver of this invention receives simultaneously both analog and digital broadcasts transmitting an identical content, changes input systems according to a reception status of the digital broadcast, and is configured in such a way that a power to an analog broadcasting receiver is controlled according to the reception status of the digital broadcast. In this configuration, based on the reception status of the digital broadcast, it is possible to reduce power which is otherwise unnecessarily consumed.
In a receiving circuit of a mobile telephone apparatus the incoming baseband signals are demodulated and equalized so as to compensate for deficiencies (multipath propagation) of the radio medium between base station and mobile telephone apparatus. It is not, however, always necessary to equalize the demodulated signals, for instance at low symbol rates or in the case of monopath propagation. According to the invention, time dispersion of the received signals is estimated prior to demodulation, and demodulation with equalization (3a) is effected when the time dispersion is established to be higher than a given value, whereas demodulation without equalization (3b) is effected when the time dispersion is lower than this value. This will enable the power consumed by the receiving circuit to be reduced, particularly in the listening mode of the apparatus.
A method and apparatus utilizing adaptive diversity in the base station of a cellular telephone system where during a diversity period the signal strengths of two receivers assigned to three or more sectors are continuously compared and the stronger audio output signal is switched to be used in the station signal processing circuits and where during non-diversity, relatively short time periods, samples of adjacent sectors signal strengths are measured and compared so that the adjacent sector with the strongest signal is applied to one receiver while the other receiver supplies the central sector to the other receiver for transmission to the station audio processor.
A television set has a satellite broadcast receiver which includes a BS converter and a BS tuner. A power supply voltage is selectively supplied from the BS tuner to the BS converter. The BS tuner has a selector switch for selecting an "ON" mode in which the power supply voltage is to be supplied on the BS converter, or an "OFF" mode in which the power supply voltage is not to be supplied to the BS converter. A control unit in the BS tuner displays on a CRT a message indicating that the power supply voltage is not supplied to the BS converter if the selector switch is selecting the "ON" mode and no BS program is being received.
A radio apparatus includes a plurality of receiving systems connected to multiple antennas providing diversity, respectively, each receiving system including an antenna terminator and a preamplifier. After one receiving system is discriminated from another receiving system based on radio signals received by the receiving systems, respectively, a controller controls the one receiving system such that an antenna terminator is inactive and a preamplifier is active and, at the same time, further controls the other receiving system such that an antenna terminator is active and a preamplifier is inactive.
