| 摘要 |
PURPOSE:To attain circuit integration, miniaturization and to transmit a picture and sound with high quality by utilizing sufficiently the advantage of digital multiplex. CONSTITUTION:Two kinds of sound signals 12, 13 are subjected to PCM coding by using a PCM encoder 11 at first, then subjected to digital multiplex with a data signal 14 and the 1st carrier in 5MHz-15MHz, for example, is subjected to angular modulation by using a signal applied with digital multiplex with a modulator 15. Then the signal subjected to angular modulation and a video signal 16 are subjected to frequency division multiplex at a synthesizer 17 and the 2nd carrier of 10MHz-100MHz is modulated by using a signal subjected to frequency division multiplex by a modulator 18. Since the multiplexed signal calls for linearity and an electrooptic conversion is nonlinear, the modulation has only to be executed by a PFM in advance. Thus, the linearity is kept, the S/N is improved and long range transmission is attained. |
