The use of filters in medical devices have not only expanded tremendously but they have also become an important part of the electrocardiography (ECG). Filters are considered essential to the ECG device because they enable the device to separate and restore its contaminated and distorted signals as well as enhance its performance. Based on the review of the previous works on filters, this paper provides insight into their nature and uses as well as examines several of the most common filtering techniques used in ECG.

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