RESUMEN
In order to enhance the position accuracy of ablation catheter in heart electrophysiology operation, signals of respiration and heartbeat must be removed for subsequent data processing. Based on locating principle of electrical field with low frequency, synchronous detector with MC1496 has been developed in this study. In the present research, several methods are utilized to optimize the circuit performance, such as coupling and stopping direct current, low-pass filtering, as well as limiting ripple voltage etc. Through simulation results, it showed that the demodulation performance of the circuit was fine. Through simulation platform of thorax electric field and animal experiment, the circuit feasibility were further proved good for extracting signals of respiration and heartbeat.