| 摘要 |
<p>PURPOSE:To facilitate the mode switching even in the darkness, by providing a vibration pickup device like a microphone, etc. to a device which requires the mode switching and then detecting the number of vibrations applied to the device to perform the mode switching. CONSTITUTION:A vibration pickup device PU1 like a microphone, etc. is provided to the set of a device like an audio tape recorder, etc. which requires the mode switching. When the set is knocked with a finger, etc., the PU1 detects the vibration due to the knocking. The detected signal is fed to a comparator 4 after amplification 2 and wave detection 3. The comparator 4 compares the detected signal with a certain level and delivers a square waveform to feed it to monostable multivibrators 6 and 6' via OR circuits 5 and 5' respectively. The vibrator 6 delivers a short pulse to a counter 7, and the counter 7 feeds signals to an FF8 from Q1-Q4 in response to the number of pulses. The vibrator 6' delivers a mask pulse (e) for about one second after the rise of the input signal to the FF8. The FF8 has an AND between the pulse (e) and the signal supplied from the counter 7 and delivers mode switching signals corresponding to the knocking frequencies.</p> |
