Digital signal processing and data analysis are frequently used techniques in biomedical engineering research. This paper
illustrates exploitation of digital signal filtering on electrocardiogram (ECG). Proposed filters are spotlighted on eliminating supply network
50 Hz frequency and breathing muscle artefacts. Furthermore, this manuscript contains depiction of three heart rate frequency detection
algorithms from ECG. Algorithms are focued on statistical and differential mathematical methods. All of the methods are compared on stress
test measurements. All described methods are suitable for next simple implementation to a microprocessor for real-time signal processing
and analysing.