Coherent noise cancelling filter
Efficient cancelling of AC line interference in electronic instrumentation
Power line carrier data transmission systems having signal conditioning for the carrier data signal
Adaptive line noise canceler and detector for ECG signals Patent #: 6041250
AbstractA power line adaptive noise cancellation system receives noise signals from house power lines and adaptively cancels the received noise from a power line input signal. The system includes a power line input signal receiver, at least one power line noise signal receiver and an adaptive noise cancellation device. The input signal and the noise signals are bandpassed filtered and demodulated by a local oscillator to generate baseband signals for both the input signal as well as the noise signals. The noise signals are input into adaptive filters that filter the noise signal based on a set of adaptive weights. The output of the adaptive filters are subtracted from a delayed baseband input signal to generate a received input signal. The received input signal is also fed back to the adaptive filters for updating adaptive weights of the adaptive filters.