| 摘要 |
PURPOSE:To improve the shortage of reaching range, the deterioration in directivity and the reduction in response speed in using an ultrasonic remote controller by providing a pulse width compensating function in addition to a function of a waveform shaping circuit . CONSTITUTION:When an ultrasonic wave signal is transmitted to a resistor 10 and a transistor(TR) 8 is turned on, a TR3 is turned off rapidly and a TR7 is turned on. Further, this inverted state is maintained for a time determined by a time constant comprising a resistor 4 and a capacitor 5 and after the time is elapsed, the TR3 is turned on and the TR7 is restored to the off-state. Thus, when the signal passes through the waveform shaping circuit, the output voltage waveform of a prescribed pulse width is obtained without being affected by the input pulse width. Then, even if the ultrasonic wave pulse is incoming from a remote distance or a position critical to the sensitivity in the direction exerting bad directivity, a stable and sure responsiveness is attained. |
