| 摘要 |
PURPOSE: A lock detecting method of a symbol synchronous circuit is provided to be capable of reducing an affect due to a noise by using an absolute value of a lock state detection signal of a symbol synchronous circuit. CONSTITUTION: A lock detecting method of a symbol synchronous circuit comprises obtaining an absolute value of a BPSK signal of detecting a lock state of the symbol synchronous circuit(90). The absolute value is accumulated by a predetermined frequency, and then the accumulated value is compared with a predetermined threshold value. Whether the symbol synchronous circuit is locked is judged according to the comparison value. The symbol synchronous circuit(90) consists of a voltage-controlled oscillator(50), a loop filter(70) and a timing error detector(80). The loop filter(70) drives the voltage-controlled oscillator(50) according to an output value of the timing error detector(80) so as to adjust a clock used in each analog-to-digital converter(40a,40b).
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