| 摘要 |
PURPOSE:To simplify a circuit and to attain miniaturization and economy by taking a signal having a noise waveform in a sound frequency band attended with a polarity inversion signal and a waveform of opposite polarity as a compensation output and suppressing the production of noise by using this compensation output. CONSTITUTION:A signal differentiated by capacitors 9, 9' from two normal N and reverse R control information input terminals 5 is applied to the bases of transistors (TRs) 10, 10'. Since the TRs 10, 10' constitute a differential amplifier of emitter coupling, a balanced output of opposite phase is obtained to the collectors of the TRs 10, 10' with a high impedance. Thus, this circuit is taken as a compensation circuit 6 and the output is applied to an output of a polarity inversion noise eliminating filter 3' via DC cut-off capacitors 7, 7', then a desired output is obtained without disturbing the characteristic of the filter 3'. Thus, the noise eliminating filter is simplified and the solid-state constitution is attained easily for the circuit 6, then the miniaturization and economy are attained. |
