| 摘要 |
PURPOSE: A demodulator for automatically compensating the gain of carrier tracking PLL is provided to reduce the overhead of the system software by not controlling the gain in response to the checking result of the lock signal. CONSTITUTION: A demodulator for automatically compensating the gain of carrier tracking PLL includes a carrier tracking PLL(10), a lock detector(300), a sweep controller(200), a first register(500), a second register(600), a multiplexer(700) and a system software(400). The carrier tracking PLL is provided with a carrier tracking PLL filter. The lock detector generates the lock signal. The sweep controller performs the sweeping operation to add the gradually increasing value to the nominal input frequency as a minimum input frequency. The first register stores the filter gain value at the acquisition state. The second register stores the filter gain value at the steady state. The multiplexer outputs one of the outputs of the first or the second registers to the carrier tracking PLL filter. And, the system software performs the program for each of the gain values of the first and the second registers.
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