DEVICE FOR MEASURING RESONANT FREQUENCY OF CONSTRUCTION MEMBERS Russian patent published in 1994 - IPC

FIELD: testing dynamic characteristics of construction members. SUBSTANCE: device has sweep-frequency control unit 1, master oscillator 2, amplitude regulator 3, power amplifier 4, vibration table 5, choppers 7, 8, matching amplifiers 9, 10, phase detector 11, feedback unit 12, frequency-to-voltage converter 14, null detector 13, commutators 15, 16, decoder 21, flip-flops 17-20, delay gates 32-36, analog-to-digital converters 2 and 23, pulse counters 24, 25, clock 29, switch 30, pulse rate dividers 26, 27, indicator 31. Adder 28 and AND gate 38 decrease bit-length of pulse counter 24 and rate of pulses entering subtraction input of pulse counter. This results in decreased probability of errors. EFFECT: increased stability to noise, increased reliability. 2 dwg