GENERALITIES. Working Principles. Loop Components. General Equations. Phase-Locked Loop Stability. LINEAR BEHAVIOR. Transient Response. Sinusoidal Operating Conditions. Additive Noise Response. Response to Random Modulations. Parameter Variation. NONLINEAR OPERATION. Natural Acquisition of the Input Signal. Acquisition Subsidiary Devices. Nonlinear Operation in the Presence of Noise.

This paper describes a new family of FM detectors having extremely low delay with excellent sensitivity. It is achieved by the use of zero group delay circuits, balance at RF, quasi-synchronous detection, and carrier cancellation. The components are compatible with integrated-circuit technology. The performance of the detectors is analyzed for both narrow- and wide-band modulation conditions indicating low distortion under normal operating conditions. However, important differences in response to transient signals exist between various detectors of the new family. Advantages are indicated over the conventional limiter-discriminator for sine wave interference conditions. Realization of the detection is discussed, and performance results of a working model are shown.