| 摘要 |
A feed-back type emphasis circuit is disclosed which comprises an input amplifier, a low pass filter, an output amplifier and a feed-back amplifier. The input amplifier receives an input through its positive terminal, and the low pass filter receives the output of the input amplifier, and supplies its output to both the output amplifier and the feed-back amplifier. The output amplifier receives the output of the low pass filter and the input from the outside, while the feed-back amplifier receives both the output of the low pass filter and the input from the outside, with the polarities of its input terminals being shiftable correspondingly with the system specification of the set. The feedback amplifier includes a differential amplifier with adjustable gain and balance for two inputs, whereby the amount of emphasis can be adjusted and the circuit of the present invention can satisfy any specification, thus no new circuit is required when the specification is changed.
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