| 摘要 |
<p>A tuning device for musical instruments, which includes: harmonic filters for the prevention of zero transits of the tone frequency voltage extraneous to the fundamental tone oscillation or to the second or fourth harmonic, a Schmitt-trigger for the conversion of the filtered tone frequency voltage into a digital oscillation, an oscillation counter with decoder and display means to the input of which the digital oscillation signal together with the reference period signal is fed via an AND-gate and which is reset by the signal for lacking amplitude of the tone frequency voltage, a reference frequency source, a reference period generator, triggering means for triggering the reference period generator, a flip-flop for the generation of an oscillation period signal, and a synchronizing device for synchronizing the beginning of the counting period with the reference frequency voltage.</p> |
