对于PLL是否锁定，您可以设置MUXOUT输出为Digital Lock Dectect模式。如果锁定，MUXOUT输出为高电平。
The ADF7020 also supports automatic detection of the sync or ID fields. To activate this mode, the sync (or ID) word must be preprogrammed into the ADF7020. In receive mode, this preprogrammed word is compared to the received bit stream and, when a valid match is identified, the external pin INT/LOCK is asserted by the ADF7020.
This feature can be used to alert the microprocessor that a valid channel has been detected. It relaxes the computational require-ments of the microprocessor and reduces the overall power consumption. The INT/LOCK is automatically deasserted again after nine data clock cycles.
The automatic sync/ID word detection feature is enabled by selecting Demodulator Mode 2 or Demodulator Mode 3 in the demodulator setup register. Do this by setting Bits R4_DB[25:23] = 010 or 011. Bits R5_DB[4:5] are used to set the length of the sync/ID word, which can be 12, 16, 20, or 24 bits long. The transmitter must transmit the MSB of the sync byte first and the LSB last to ensure proper alignment in the receiver sync byte detection hardware.
For systems using forward error correction (FEC), an error tolerance parameter can also be programmed that accepts a valid match when up to three bits of the word are incorrect. The error tolerance value is assigned in Bits R5_DB[6:7].
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