| 摘要 |
PURPOSE:To obtain an even lead-in range to each input frequency, by varying the band pass characteristics synchronously with the composite signal for a low-pass filter provided at the output side of a phase comparator. CONSTITUTION:The free-running frequency of the voltage control oscillator 3 is set to be the standard frequency of a musical tone. Then the standard frequency is compared with the frequency of the musical tone through the phase comparator 1. The output of comparison is applied to the oscillator 3 via the low-pass filter 2, and the oscillation frequency is led into the frequency of the musical tone. The means 9 is provided to vary the band pass characteristics within the filter 2, and the band pass characteristics is varied according to the frequency component. As a result, an even lead-in range can be obtained for the frequencies from the basic wave to a higher-order harmonic wave. |
