The SCEM-Phase-Lock Loop and Ideal FM Discrimination

The conventional phase-lock loop requires a low-pass filter in the loop to eliminate the double-frequency terms which arise in the phase detector. Because of this filtering, the closed-loop bandwidth is necessarily small. A new phase-lock loop is introduced, the SCEMPLL, whose phase detector requires no filtering; hence, this phase-lock loop has a wide closed-loop bandwidth and, resultantly, approaches the performance of an ideal FM discriminator.