Spent researches show that one of mechanisms of human auditory system ensuring high noise resistance of vocal speech sounds recognition is an electromechanical envelope feedback, effecting in structures of inner ear in man. Digital modeling of hearing system peripheral section with a similar multichannel envelopes feedback has shown to be useful for pitch determination of vowels in noisy environment. The offered model provides robust pitch detection for signal/noise relation up to -12 - -14 dB. In number of cases such a noiseproof feature is better than for other existing methods and systems.