Discriminators for Instantaneous Frequency Measurement Subsystem Based on Open-Loop Resonators

The authors have studied a new way to design an instantaneous frequency measurement subsystem (IFMS). The method is based on bandstop filters. The device uses rectangular open-loop resonators instead of delay lines. The resonance frequency is adjusted by a resonator perimeter that must be approximately a half-wavelength long, and also by coupling distance between the resonators and the main transmission line. Simulated and experimental results are presented for a 5-bit IFMS.