| 摘要 |
PURPOSE:To prevent the waveform of an output signal from being distorted and to prevent sound quality from being degraded by changing a resistance value between a resonance circuit and a reference potential point and changing the boost amount of a boost circuit corresponding to the damping amount of an input signal due to a volume part by a boost amount adjusting means. CONSTITUTION:When data for control are inputted through terminals 10, 11 and 12 so that the damping amount can be OdB, switches Sa1, Sb1 and Scm+1 are turned ON. The gain of low area and high area frequency components is reduced in the output end of a mix amplifier 21 and the signal of a flat frequency characteristic appears in the output terminal. Next, when the damping amount is -5dB, switches Sa1, Sb6 and Scm are turned ON based on a control signal from a logic circuit 13. For the low area and high area frequency components in the output end of the mix amplifier 21, the gain is enlarged in comparison with the case of the damping amount OdB. Similarly, when the damping amount is gradually enlarged, switches Scm+1 to Sc1 are successively changed over and the boost amount is enlarged in low and high areas. Then, the frequency characteristic can continuously be changed. |
