| 摘要 |
PROBLEM TO BE SOLVED: To provide a simple and inexpensive audio equipment. SOLUTION: The graphic equalizer circuit 12 of the audio equipment 10 includes an adder 121 that receives an audio signal at its one input and an output signal of a band pass filter whose gain is adjusted by a gain adjustment resistor 124 is given to the other input of the adder 121. An output of the adder 121 is given to an inverting amplifier 125, where the signal is inverted. A switch 122 is used to select whether the audio signal is given to the band pass filter 123 or an output signal of the inverting amplifier 125 is given to the band pass filter 123. Thus, the band pass filter 123 is used in common for a graphic equalizer filter and for a spectral analyzer filter. |
