Patent ID: 11965919
Assignee: ZHEJIANG UNIVERSITY
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G

Claim 2:
3. The phase frequency detector-based high-precision feedback frequency measurement apparatus according to claim 2, wherein the FPGA (3) comprises an equal-precision frequency measurement module (301), a precise frequency measurement module (302), and a frequency measurement processing module (303); the equal-precision frequency measurement module (301) receives one path of signal of the measured time-frequency signal (9), and roughly measures to obtain a measured signal fx; the precise frequency measurement module (302), the phase frequency detector (5), the charge pump (6), the low-pass filter circuit (7), the A/D converter (8), and the DDS (4) form a negative feedback system to adjust the reference signal fx′ synthesized by the DDS (4) until reaching a stable state, that is, a precise measurement process is realized within an error range of fx′=fx; and the frequency measurement processing module (303) is used for detecting a rough measurement completion signal of the equal-precision frequency measurement module (301), and enabling the precise frequency measurement module (302).