| 摘要 |
PURPOSE:To convert the sound wave directly into the digital sound signal. CONSTITUTION:An oscillation part 2 has opposing electric stations 11, 12, oscillates a receiving sound part 1 for which the capacitance changes according to the sound wave as a part of the resonance circuit and transmits an oscillation signal S1. A reference frequency generation part 3 generates a reference signal S3 having the frequency which is almost equal to the frequency of the oscillation signal S1 in the silent state. A mixture part 4 receives the oscillation signal S1 and the reference signal S3 and generates a signal S2 having the frequency of the difference of the both signals. A counter part 5 counts the frequency of the signal S2 and the countes value is outputted as digital data D1. A gate part 7 generates a digital parallel signal D2 by sampling the digital data D1 by a sampling clock C and a parallel serial conversion part 8 converts the digital parallel signal D2 into the prescribed format serial digital sound signal D3. |
