| 摘要 |
The recording amplifier (7), which as usual has an automatic recording level control and effects a boosting of the higher audio frequencies, is utilised during playback. The output signal of the playback amplifier (4) is fed via a high-pass filter (6) to the input of the recording amplifier (7), whereas the output signal of the recording amplifier (7) passes together with the magnetic-tape playback signal in a way providing degenerative feedback via an adding stage (3) to the input of the playback amplifier (4). If the signal emitted by the sound head (1) drops below a level of, for example, -30 dB, the recording amplifier (7) is adjusted in such a way that the degenerative feedback causes an attenuation of the higher-frequency signal components, to be precise all the more intensely the lower the signal amplitude is at the input of the recording amplifier (7). This is a way of achieving with little expenditure effective noise suppression which is effective also in the case of brief signal breaks if the time constant of the recording level control in the recording amplifier (7) is reduced during playback by the factor 1:100. <IMAGE> |
