Real time QRS detector based on field programmable analog array

In some applications it is important to detect the QRS complex in the ECG waveform with possibly low time delay. Traditional software detectors of the QRS complex implement algorithms usually based on cascades of digital filters that introduce delays up to parts of a second. On the other hand, hardware QRS detectors fulfil the low delay requirements, but have worse adaptive features for the changing ECG shape. In this paper a new approach to QRS detection is presented. The proposed detector is based on a Field Programmable Analog Array (FPAA). This solution makes it possible to modify the parameters of particular blocks of the detector or even the whole structure without any changes in hardware, while the processing path is fully analog and does not introduce an additional delay. The most interesting feature of the FPAA is the dynamic reconfigurability. The parameters can be changed during runtime without any reset of the circuit or any other disturbances of the system functionality. The prototype QRS detector was built using the AN221E04 circuit from the Anadigm company.