Frequency measurement and analysis via different frequency phase synchronization fuzzy region

A precise frequency measurement and analysis method utilizing the concept of the different frequency phase synchronization fuzzy region is presented based on the principle of phase synchronization detection. Initially, the frequency of the measured signal was roughly estimated by using the traditional high-precision time and frequency detection technology. Subsequently, the frequency estimated was fed into a direct digital synthesizer (DDS) to generate a real-time frequency standard signal that exhibited a slight frequency deviation relative to the measured signal. The edge pulses of the different frequency phase synchronization fuzzy region served as counter switch signals, enabling the counting of both the detected signal and the real-time frequency standard signal within a specified gate time. Through subsequent data processing of the obtained values, the frequency, frequency difference, and frequency accuracy of the detected signal could be determined. Experimental results demonstrate that the system based on this method achieves a frequency stability of 10⁻¹³ at 1 s, with a frequency deviation of less than 3 Hz. Compared with traditional frequency measurement and analysis methods, this approach has many advantages, especially its fast response time of less than 1 ms, high measurement accuracy of more than 10⁻¹¹ at 1 s, high integration with only one FPGA chip, and cost of less than 1000 yuan. It is widely applied in the fields of time and frequency services and security technology of the Beidou satellite (BDS) navigation system, such as BDS pseudo-range measurement, Beidou positioning, navigation and time services, as well as precise time and frequency measurement and control, etc.