| 摘要 |
PURPOSE:To improve the realization of a timing extraction circuit of a high speed PCM signal transmission system and to obtain an identification circuit by adopting a high Q surface acoustic wave filter suitable for the use at a 1/N frequency region. CONSTITUTION:The subject transmitter is constituted of latch circuits (101-1)-(101-N), OR circuits 103, 109, a 1st timing extraction filter 104, a 1/N frequency divider circuit 105, a 2nd timing extraction filter 106, a clock distribution circuit 107 and a delay circuit 108, etc. Then the 1st timing extraction filter 104 extracts a coarse timing component from an input signal, the coarse timing component is frequency-divided into 1/N frequency region by the 1/N frequency divider circuit 105 and a clock signal is generated at a highly stable timing. Then the clock signal is divided into N and fed to the latch circuits (101-1)-(101-N), and the 2nd OR circuit 103 takes logical sum among the results of identification by 1/N frequency each to obtain an identification reproduction signal. Thus, the realization of timing extraction circuits in high speed PCM signal transmission system and the realization of an identification circuit and a transmitter are improved. |
