Abstract: A CPU limits the operation of a television receiver unit, and permits the operation of a mobile telephone radio-communication unit when a battery's voltage is lower than the threshold (operation control threshold) stored in memory.

Abstract: In order to provide a radio selective calling receiver that can display a message in language at the current location without making a user recognize the current location, character fonts are automatically switched on the basis of the area information contained in a reception signal.

Abstract: An information receiving apparatus is disclosed, which comprises: storing means for storing pairs of area information assigned for predetermined areas and area name thereof; area information detecting means for detecting area information contained in received information; area name detecting means for detecting an area name of the current position of the apparatus corresponding to the detected area information with reference to the storing means; searching means for searching for a message element for the area name of the current position of the apparatus among a message in the received information; and displaying means for displaying the searched message element on a displaying portion.

Abstract: A radio receiver receives a 4-FSK signal through a radio system and a detector detects a four-level detected signal from the 4-FSK signal. The four-level detected signal is converted into digital form by an AD converter. The digital signal is stored onto a memory. The AD conversion is performed at intervals obtained from the four-level detected signal. A CPU performs the data processing of the received digital data when the AD conversion is not performed and does not perform it when the AD conversion is performed.

Abstract: In a radio pager capable of receiving a paging signal subjected to multilevel digital frequency modulation, an analog-to-digital converter (ADC) receives a demodulated voltage signal in the form of an analog signal from a demodulator. The ADC functions to define the upper limit of an analog signal conversion range with a first reference voltage and to define the lower limit of the same with a second reference voltage. Even when at least one of the demodulation sensitivity and demodulated center voltage of the demodulated voltage signal changes with a change in temperature and causes the signal to change, the relation between the signal range of the demodulated voltage signal and the analog signal conversion range of the ADC is maintained constant. Therefore, even if the demodulated voltage signal before temperature compensation changes, the ADC is capable of outputting a stable digital signal identical in content or data with an intermediate frequency signal input to the demodulator.