With advances in the manufacture of super great integrated circuits, a commercially available element base that realizes the sigma-delta (sigma-delta) analog-to-digital conversion principle in one microcircuit has appeared. The sigma-delta analog-to-digital converters (ADC) have a high resolving power (above 12 bits), they are largely based on the signal digital filtration principles, which may moderate requirements for the analog filtration of signals and use direct-current amplifiers as alternatives to instrument ones. For electrocardiograph operation, the sigma-delta ADC of an AD 7716 (Analog Devices) with 22 bits were used in this study. The use of sigma-delta ADC in the electrocardiographs has been shown to be a rather useful alternative of traditional ADC. Moreover, sigma-delta ADC may be also useful for other systems for collecting and processing biomedical signals which are close in their requirements for a frequency range and a dynamic range, i.e. encephalographic, myographic, rheographic and other input signals.