In this work a new version of the cross-coupled phaselocked loop (CCPLL) interference canceller is presented. This detector consists of two phase-locked loop (PLL) demodulators interconnected in such a manner as to permit one PLL to lock onto and track the instantaneous frequency of the stronger received signal, while the other loop tracks and demodulates the weaker of two received signals. In addition, the receiver includes control loops to estimate the instantaneous amplitude of both received signals. This demodulator, therefore, has the capability of detecting both the desired and interfering signals, even though the interferer may be stronger than the desired signal and may share the same frequency band. The defining nonlinear differential equations for the CCPLL structure are derived and transient acquisition responses are obtained using computer-aided analysis. The CCPLL has numerous technological applications in suppressing a wide variety of cochannel and adjacent channel interferers.

In this work, the acquisition behavior of a cross-coupled phase-locked loop (CCPLL) FM demodulator capable of suppressing cochannel and adjacent channel interferers is examined. This novel detector consists of two phase-locked loop (PLL) demodulators interconnected in such a manner as to permit one PLL to lock onto and track the stronger received signal, while the other loop tracks and demodulates the weaker of two received signals. The demodulator has two separate outputs, namely, the outputs of each PLL, and thus possesses the capability of demodulating both the stronger as well as the weaker received signals even though they are cochannel and share the same frequency band. The transient response of the CCPLL system is obtained using computer-aided analysis of the defining coupled nonlinear differential equations. From these results, steady-state "stability regions" are derived which reveal that range of loop parameters where successful separation and demodulation of the received cochannel signals is assured. The CCPLL receiver has numerous technological applications in suppressing unintentional or intentional CW, AM, FM, and AM/FM interferers. Experimental results demonstrating such potential are included.

In this paper an FM detector capable of suppressing the degradation in receiver performance due to the presence of an interfering signal is presented. Optimum receiver structures based on maximum-aposteriori estimation procedures are first derived and then a practical demodulator based on the optimum receivers is examined. The receiver consists of two phase-locked loops (PLL) interconnected in a manner to permit one PLL to lock onto and track the Stronger received FM signal while the other loop tracks the weaker of the two received FM signals. The detector has the capability of demodulating both the desired received FM as well as the interferer even for the case when both signals are co-channel. Experimental results demonstrating such capability even in the presence of strong input Gaussian noise are presented.