DSP2812 software phase lock problem

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DSP2812 software phase lock problem [Copy link]

1. Phase lock The meaning of phase lock is the automatic control of phase synchronization. The automatic control closed-loop system that can complete the phase synchronization of two electrical signals is called a phase-locked loop, or PLL for short. There are three methods of software phase lock: pointer zeroing method, frequency modulation first and then phase modulation method, and frequency modulation and phase modulation at the same time method. 2. Pointer zeroing method: The pointer zeroing method is the simplest software phase lock method. In the Cap1 interrupt that captures the zero-crossing point of the input voltage signal, the pointer of the sine point is directly zeroed to ensure that the output reference issued by the DSP also crosses zero when the input voltage signal crosses zero, thereby achieving phase synchronization. The pointer zeroing method is suitable for the case where the input frequency is stable. 3. Frequency modulation followed by phase modulation: The sine reference table is composed of n data. A variable Sinpoint is set as the pointer of the sine table to indicate the phase of Uref. When the rising edge of the input voltage is captured,

DSP2812 software phase lock problem