| 摘要 |
<p>PURPOSE:To shorten an initial unstable period at the time of the start of input by providing an R1C1 series circuit for removing a bias output, an R2C2 parallel circuit which removes noises and also determined an operational amplification degree, and a high-pass filter, and combining the high-pass filter with a changeover switch means. CONSTITUTION:When a switch knob 25 is pressed in as shown by an arrow 32, switch states 39 and 40 are both on for an extremely short initial time and a signal from an input terminal 11 is inputted to both resistances 91 and 93 at this time. Consequently, a time tau up to the stabilization of the high-pass filter 21 is proportional to the product of the resistance 91 and a capacitor 101, so the resistance value of the series R1C1 circuit becomes temporarily small because the resistance 93 is connected in parallel. The time constant of this circuit, therefore, decreases below the initial value temporarily and the time up to the stabilization is short. For example, when the resistance 91 is set to 3 MOMEGA, the capacitor 101 is set to 1 muF, and the resistance is set to 100 kOMEGA, the time up to the stabilization of the high-pass filter 21 is about 0.1 second.</p> |
