| 摘要 |
PURPOSE:To set the capacitance of a capacitor small and to increase the Q of an equivalent inductance, by using a resistor and a capacitor for each admittance of a gyrator circuit as specified. CONSTITUTION:Y4-Y8 are admittances of each element, 1-3 are nodes of this circuit, and V2, V3 are voltages at nodes 2 and 3 respectively. The relation between input terminals Vin and V2 of input terminals 1a, 1b and an output Vout of an operational amplifier 4 is expressed in equations 1 and 2. Thus, an input impedance Zin is expressed in equation 3. Where Y5Y7=Y6Y8 is satisfied, equation 3 is simplified into equation 4. Taking Y4=SC, Y5=1/R5 and Y8=1(that is, resistors R5, R8 are used for Y5, Y8 respectively and a capacitor C is used for Y4) in equation 4, a series circuit of R and L is obtained as given by equation 5. In equation 5, the resisters R5, R8 are included in the imaginary part and the capacitance value of the capacitor C can be set arbitrarily independently of the Q of the equivalent inductance to some extent. Thus, said Q can be increased. |
