GNDA_PLL

the difference

The difference between analog phase locked loop and digital phase locked loop.

The main difference between bai and nonsense is that the former is realized by analog du circuit, while the latter is designed with digital modules. If dao is a fully digital phase-locked loop, there is no analog part. The following is A paragraph I set up:

The phase-locked loop is a feedback control circuit, whose function is to synchronize the external input signal of the device with the internal oscillation signal. At present, phase-locked loops are widely used, such as: used in communication systems such as modulation and demodulation automatic frequency fine-tuning; in radar, used in antenna automatic tracking and precision auxiliary angle deflection measurement systems; in space technology, mainly used in speed measurement and orbit determination , Ranging and remote measurement data acquisition systems; used in TV sets for synchronous detection of TV synchronization and threshold extension demodulation. The traditional analog phase-locked loop has a short lock time, which can ensure the steady-state phase difference between the reference clock source and the output clock. However, its center frequency is limited by the VCO, and the loop bandwidth is relatively small. When the reference source is interrupted or the reference clock source is switched, the VCO output clock frequency will have a large phase transient. Compared with the PLL implemented by the traditional analog circuit, the all-digital phase-locked loop (DPLL) has high accuracy and is not affected by temperature and voltage. The loop bandwidth and center frequency can be programmed and adjusted. When applied in a digital system, it is unnecessary A/D and D/A conversion.