| 摘要 |
In a loudness control circuit, the output DC voltage of a first variable DC voltage source is applied to a first amplifier for increasing volume to vary the gain of the latter, and to first and second differential amplifiers, while the output DC voltages of second and third variable DC sources are applied to the first and second differential amplifiers to provide difference voltages, which the applied to second and third tone control amplifiers which amplify the low and high frequency ranges, respectively, to control the gains thereof, so that the components of the sound in the low and high frequency ranges are boosted, thus achieving the weighting.
|
