Abstract: The rise-up time of an intermediate frequency signal generated in a radio receiving unit is detected at each time in intermittent receiving operation. The radio receiving unit is turned on for a period including the rise-up time and a time of the intermittent receiving operation. Consequently, the electric power consumption of a battery for a power supply of the radio receiving unit is decreased.

Abstract: In order to obviate the tendency for batteries to be changed at an overly early timing, the battery voltage is monitored and a first alarm is issued when the battery voltage drops below a predetermined level. The issuance of the first alarm sets a timer which times a predetermined period and issues a second alarm upon the expiration thereof. The length of the predetermined period may be adjusted by the user and the time from the issuance of the first alarm may be shown on a display upon demand.

Abstract: In a hand-held electronic apparatus, such as radio display pager, a control circuit is powered by a first battery to produce an control signal for operating an inductive device such as vibrator. A second battery is provided having an internal resistance lower than the internal resistance of the first battery. A capacitor is connected in parallel with the inductive device and the voltage developed thereacross is monitored by a voltage sensor, which produces a sensor output when the voltage exceeds a prescribed level. A first switching circuit is responsive to the control signal for coupling the inductive device to the second battery and responsive to the sensor output for decoupling it from the second battery. A second switching circuit also responds to the sensor output for coupling the inductive device to the first battery until the control signal ceases to exist.

Abstract: A radio pager having means for automatically adjusting the rising time of a high-speed clock. The pager includes a plurality of circuit elements for adjusting the rising time of the high-speed clock, i.e., for compensating the degree of stability of a high-speed clock generating circuit. On the start of a low-speed clock, the high-speed clock generating circuit sequentially selects and connects the circuit elements to thereby count the resulting rising times of the high-speed clock. One of the circuit elements having resulted the shortest rising time is written to a storage. When the high-speed clock is needed, e.g., when a message should be displayed, the stored circuit element is connected to the high-speed clock generating circuit.

Abstract: A paging receiver provided with a speaker unit including a first resonant box and a second resonant box in order to produce a higher sound pressure without however enlarging a casing of the receiver body is disclosed. The second resonant box is formed made in a hollow space of a mold for fixing a holder to the casing of the paging receiver and is provided with slits to resonate in response to the sound wave outputted from the first resonant box at either input or output portion of the sound wave.