| 摘要 |
FIELD: agriculture; public utilities; food industry enterprises. SUBSTANCE: for frightening off the rodents amplitude-modulated acoustic signal is generated. Signal carrier frequency equal 30-50 kHz at modulation frequency of 0.5-10.0 Hz and modulation depth of 10-90 per cent. In process of generation, modulation depth is varied continuously or in steps. EFFECT: more effective control. 4 cl, 1 dwg øøø1
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