| 摘要 |
PROBLEM TO BE SOLVED: To reduce electric power consumption and to obtian a portable telephone of a low cost by controlling an oscillation frequency of an oscillator built-in signal processing IC with a digital signal arithmetic processing unit, sweeping the frequency and intermittently vibrating a speaker. SOLUTION: The oscillator is built in a CORDIC IC 103 and the frequency of the oscillator is controlled by a DSP(digital signal arithmetic processing unit) 1-4. Namely, instructions are issued at specified intervals to continuously vary the frequency and to sweep the frequency. The frequency fin of the signal to be inputted to the CORDIC IC 103 is set at 256 kHa and the constant (n) for frequency setting at a prescribed value from the set frequency f=fin/[12×(1+n)]. The frequency is shifted at time intervals of 0.5 to 1.5 msec by using such frequency range, by which the intermittent operation of the vibration is executed. |
