Power-supply interference is often associated with the measurements of electrical and non-electrical quantities specially with the recording of electro-physiological signals. This paper describes a novel filter circuit to suppress power-supply interference. The circuit described here uses digital techniques and has following special characteristics: (i) The rejection-filter circuit possesses a high value ofQ. (ii) The filter eliminates harmonic frequencies also. This property helps in eliminating power supply interference still further because in most cases the waveform of the supply is not pure sinusoidal. (iii) The filter has tracking characteristics and any variation in power-supply frequency is automatically taken care of i.e., tuning of the filter is not required.
展开▼
