| 摘要 |
<p>PURPOSE:To transmit even a signal which is not processed at all to an output side and to display its signal intensity securely by providing a means which by- passes an input signal and a means which sets an amplification degree to other than one when respective band components are amplified or attenuated. CONSTITUTION:Plural amplification blocks 26 of a graphic equalizer are each provided with a BPF9 wherein a band to be selected is set, an amplifier 10 which amplifier or attenuates only the band component corresponding to the BPF9, and a switching circuit 12 which changes amplification degree of the amplifier 10. The difference signal between the input signal and output signal of the amplifier 10 is obtained by a subtracting circuit 18 and applied to a display device 8a through a converting circuit 20. When the amplifier 10 neither amplifies nor attenuates the input signal, a by-pass switch 25 is placed on the side of a contact A to by-pass the input signal to the output side. Further, an OR circuit 25 which inputs switching signals D13 and D7 and controls a switch 13 by its output is provided to set the amplification degree of the amplifier 10 to other than one.</p> |
