A Novel Method Based on Probability Density Function Used in Instantaneous Frequency Measurement System for Wider Range and Less Error

This article reports a photonic-assisted instantaneous frequency measurement system based on a multi-group asymmetrical Mach-Zehnder interferometer structure, applicable in contemporary electronic countermeasure. Additionally, we introduce a novel method to obtain measurement results based on probability theory. Employing this method allows for a broader measurement range compared to traditional approaches utilizing amplify compare function without a deterioration in accuracy. Sufficient and systematic experimental results show that the measurement range can be at least 30 GHz and the mean error is 0.102 GHz using our proposed system and method. Moreover, we propose an optimization algorithm based on our method. By using this algorithm, we can adjust measurement range for proposed system with minimal asymmetrical MZI structures, ensuring no compromise in accuracy. In addition, the system is easy to realize hybrid integration or even monolithic integration due to the use of microwave photonics technology.