Digital signal will be affected by noise during transmission, which will lead to signal amplitude distortion. Although the analog signal must be amplified by the repeater after a certain distance transmission, the noise will also be amplified, and the noise interference cannot be removed. So with the increase of communication distance, noise will accumulate more and more. However, the regenerative relay system in digital communication can be eliminated by equalizing and amplifying the signal and judging the regeneration due to noise interference.

The so-called balanced amplification is to amplify the distorted signal into a waveform suitable for sampling decision (balanced waveform).

The so-called regeneration judgment means that the balanced waveform is sampled and judged, and the pulse is shaped to form the same pulse shape as the initial one.