High Resolution Microwave Frequency Measurement Using a Dual-Parallel Mach–Zehnder Modulator

A novel microwave frequency measurement scheme based on a dual-parallel Mach-Zehnder modulator (DPMZM) is proposed and demonstrated. By simply adjusting the bias voltage of the DPMZM, the measurement range can be divided into several parts and each part has very high resolution. Thus, the system can be used in a two-stage instantaneous frequency measurement scheme, in which the first stage coarsely determines the frequency band of the intercepted microwave signal, and then the proposed scheme measures the frequency with high resolution. An experiment is performed. Instantaneous frequency measurement with a frequency measurement range of 2.3-18.7 GHz and a measurement resolution of ±0.20 GHz is achieved.