| 摘要 |
<P>PROBLEM TO BE SOLVED: To facilitate changeover between an open loop gain and a closed loop gain by making a negative feedback amount constant in the entire frequency band in a phono equalizer circuit. <P>SOLUTION: The phono equalizer circuit is provided with a V/I conversion resistor circuit for converting voltage of an inputted audio signal into current and switching an open loop gain and a closed loop gain, a current mirror circuit for amplifying the current converted by the V/I conversion resistor circuit, a first RIAA (Record Industry Association of America) circuit for converting the current amplified by the current mirror circuit into voltage to make the signal have an RIAA frequency characteristic, and a second RIAA circuit for performing negative feedback of the signal made to have the RIAA frequency characteristic by the first RIAA circuit. <P>COPYRIGHT: (C)2009,JPO&INPIT |
