Inband noise cancelling in FM systems: the white noise case (original) (raw)

This letter presents an investigation into a novel noise cancellation circuit aimed at enhancing the reception quality of frequency modulated (FM) signals by reducing white noise in low carrier-to-noise ratio (CNR) conditions. The analysis demonstrates that utilizing this circuit allows for up to a 6 dB reduction in the noise floor, particularly beneficial when the CNR is below the threshold level. By employing an amplitude locked loop (ALL) along with conventional phase-locked loop (PLL) techniques, the method effectively isolates and reduces inband noise, thus maintaining signal integrity during FM reception.