| 摘要 |
<p>The gain-controlled amplifier, for LF sound systems, is designed so that its gain has already been altered by the time the input signal reaches the gain-controlled stage of the amplifier. The gain control therefore causes no audible amplitude modulation when the signal appears. The input signal is delayed and passed to the gain-controlled stage, whilst the gain-control signal is derived from the undelayed input. The delay circuit comprises an analog device such as a bucket brigade delay arrangement. The latter type can be obtained ready-made and offers a delay time between 0.5 and 1 ms.</p> |
