| 摘要 |
PURPOSE:To obtain divided periods of a desired low and a high frequency range with less parts by obtaining the difference between and the sum of outputs of two phase shifters which shift the phase of an audio signal optionally and extracting a low and a high frequency component. CONSTITUTION:The primary phase shifter 21 consisting of an operational amplifier 25, resistances R1-R3, and capacitor C1 is capable of shifting the phase of the audio signal inputted from a terminal (e) by pi radian at a maximum and the capacity value of the C1 and the resistance value of the R3 are varied to obtain optional phase characteristics. The secondary phase shifter consisting of an operational amplifier 26, resistances R4-R7, and capacitors C2 and C3 is capaable of shifting the phase of the signal by 2pi radian at a maximum and the capacity values of the capacitors C2 and C3 and the resistance values of the resistances R4 and R5 are varied to obtain optional phase characteristics. Outputs P1 and P2 of the phase shifters 21 and 22 are supplied to a subtractor 23, whose subtraction output appears at a terminal (f). Those outputs P1 and P2 are further summed up by an adder 24, whose output appears at a terminal (g). The outputs at the terminals (f) and (g) are equivalent to signals obtained through an LPF and an HPF respectively and the low frequency component and high frequency component are outputted. |
