| 摘要 |
PURPOSE:To reduce the number of parts of an audio processing circuit and to obtain a low-cost magnetic recording and reproducing device by omitting audio recording and reproducing circuits for the middle speed mode. CONSTITUTION:An equalizer circuit for recording of the two-hour mode is used for recording of the four-hour mode. In this state, audio signals are inputted and are amplified by a mike amplifier 1 and are amplified by a line amplifier 2 and are inputted to a recording equalizer amplifier 9. In the recording equalizer amplifier 9, inputted signals are biased in the equalizer circuit of the two-hour mode by a frequency characteristic for the two-hour mode and are outputted to a recording head 6 and are recorded on a magnetic tape. At a reproducing time, the mode of reproduced signals is detected by a mode detecting circuit and is given to a mode switching circuit 5'. An equalizer circuit of the six-hour mode out of equalizer circuits incorporated in a regenerative equalizer amplifier 8 is made operatable in accordance with this mode. That is, the regenerative equalizer amplifier amplifies reproduced signals so that they have a frequency characteristic of the six-hour mode, and they are amplified by the line amplifier 2 and are outputted as audio signals. |
