| 摘要 |
PURPOSE:To eliminate the need for adjustment at each channel through simple constitution by inputting a frequency division multiplex signal obtained through modulation subcarriers of each channel of the same level to a pre-emphasis circuit and applying pre-emphasis processing so that the level of the subcarrier of high frequency is increased. CONSTITUTION:Outputs (Fig. b)of stereo frequency modulators 10A, 10B...10N are formed into the same level while its level is not adjusted at each channel. Outputs of the stereo frequency modulators 10A, 10B...10N are synthesized into a frequency division multiplex signal as shown in Fig. (c) by a synthesizing circuit 12. The output of the synthesizing circuit 12 is inputted to a preemphasis circuit 14, where it is applied with pre-emphasis processing as shown in Fig. (d) so that the voltage level of the subcarrier having a high frequency is increased. Concretely, the pre-emphasis processing is applied so that the ratio of thevoltage level of each subcarrier signal and the level of the same frequency of a triangle noise N at frequency demodulation is nearly the same. |
