| 摘要 |
PURPOSE: A clock extracting apparatus is provided to achieve a safety operation of communication equipments using 8K clock signals by extracting a stable 8K clock from a 64K clock signal. CONSTITUTION: A clock extracting apparatus has an input terminal signal stabilizer(210), a signal processor(220), a 14K clock extractor(230), a 24K clock extractor(240), a clock signal coupler(250) and an output signal stabilizer(260). The signal stabilizer(210) stabilizes a positive clock signal about a positive pulse and a negative clock signal about a negative pulse from clock signals from a 64K composite clock generator. The signal processor(220) generates a digital signal. The digital signal becomes high level in a rising edge of the negative clock signal and low level in the rising edge of the positive clock signal, and is delayed for 2/3 period. The 14K clock extractor(230) generates a 4K clock signal from the output signal of the signal processor, and the 24K clock extractor(240) generates another 4K clock signal. The 4K clock signals are combined in the clock signal coupler(250). The signal stabilizer(260) stabilizes the output signal from the clock signal coupler(250).
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