| 摘要 |
PURPOSE:To set an intermediate frequency to a low frequency without causing pulse waveform distortion by synchronizing the intermediate frequency to the integer multiple of a repetitive frequency of pulse signal. CONSTITUTION:A pulse signal generator 1 generates a pulse signal 2 having a bit rate of 8Mb/s and is operated in matching with the timing of a clock signal in 8MHz. A multiplier 4 inputs the clock signal 3 and converts it into an intermediate frequency sinusoidal wave signal 5 having a frequency of 4 times. The pulse signal 2 and the intermediate frequency sinusoidal wave signal 5 are converted into an intermediate frequency signal 7 by a mixer circuit 6. This intermediate frequency signal 7 is amplified by a driving circuit 8, applied to a supersonic optical modulating element 9 and activates the supersonic optical modulation element 9. On the other hand, an output light 11 of a laser light source 10 is inputted to the supersonic optical modulation element 9 through a condenser lens 12, is subject to modulation, separated into a signal light 13 and a transmitted light 14 and outputted. This signal light 13 is coupled further to an optical fiber to transmit the signal. |
