| 摘要 |
PURPOSE:To make the frequency characteristic constant independently of the adjusted gain by converting an input signal and a control signal digitally and reading storage information of a storage element with an electrical signal combined with the converting signal so as to eliminate the effect of floating capacitance. CONSTITUTION:A signal at an input terminal (a) is converted into a digital signal in m-bit at an A/D converter 1 of a signal gain adjusting circuit and a control signal (c) outputted by the operation of the gain adjusting variable resistor 6 is converted into a digital signal in n-bit by an A/D converter 2. Both the digital signals are inputted to input terminals b1, b2 by using them as a read address of a storage element group 3. The digital signal in X-bit is outputted from the element group 3 by using the address signal and its output signal is converted into an analog signal by a D/A converter 4. This signal is outputted to an output terminal (f) via an LPF5 so as to eliminate the effect of the floating capacitance thereby making the frequency characteristic constant independently of the adjusted gain. |
