| 摘要 |
PURPOSE:To obtain a frequency characteristic variable circuit changed around a specific frequency by dividing an input into two, inputting the one into a delay circuit, the other to a variable gain amplifier circuit and adding outputs of both circuits. CONSTITUTION:A signal inputted to an input terminal 22 is inputted to a delay line 24 and the gain variable amplifier 28 via a resistor 23 equal to a characteristic impedance of the delay line, added at an adder circuit (comprising transistors 6, 31, and resistors RE, RL) and outputted to an output terminal. Since the relation between an input Vi and an output V0 is expressed as V0=(RL.Vi/RE) (1-Ax.cosbetal), where beta=2pi/lambda, l is the length of delay line, lambda is wavelength, and Ax is gain. Thus, the relation between the output and input is unchanged at a frequency fc where cosbetal=0 is established and the relation between the output and input depends on the gain Ax in other frequencies. |
