SU309627A1 - METHOD FOR DETERMINING A LOGARIFMIC ALGORITHM1 - Google Patents

Description

This invention relates to acoustic measurements.

Methods are known for determining the logarithmic decrement of damping of oscillators of the x systems by indicating the phase shift between the test signal and the reference signal.

. The proposed method differs from the known ones in that additional pulses of a multiple frequency synchronized with them are formed from the reference signal, compared with the pulses obtained from the signal under study, and according to their coincidence in time they are judged about the desired value.

This increases the accuracy and automatic recording of measurement results is possible.

FIG. Figure 1 shows a signal timing diagram explaining the proposed method; pas figs. 2 - a device for measuring the proposed method.

From the mapped Oinoptioro (Fig. 1, a) and the signals under study (Fig. 1.6), short pulses form (Fig. 1, c, d), tied to a phase corresponding, for example, to zero amplitude, and following at intervals . Synchronously with the reference signal form pulses (Fig. 1, d), following through the i-interval. These pulses are compared4

in time with the pulses shown in FIG. 1,

The coincidence of the pulses 1. G, 1 and 2, 2, 2 correspond to the phase shift between the reference h

Signals under study - Other matches will be at phase shift ± n -, where -

integer.

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The device for measuring the logarithmic decrement of oscillation of the samples (Fig. 2) contains a path 1 for oscillation excitations, states of a power amplifier 2, a frequency divider 3, a periodic oscillator 4 connected in series with sample 5, a path 6 for receiving oscillations, associated with the sample, and a time selector 7, the inputs of which are connected to the generator 4 and path b, and the output to the indicator 8 via the control unit 9 to the generator 4.

From oscillator 4, oscillations are applied to blocks 5 via generator 3 and 2, which are detected by path 6. Pulses from geierato 4 signals and path 6 are fed to time selector 7.

The measurements control the frequency of the oscillator 2 and measure it at discrete phase shifts received by the 6 sial block.

Prevention and Consideration

The method for determining the logarithmic decrement of the damping of oscillatory systems, for example, samples of the material, the numeric and the discrete values of the phase shift between

the test and reference signals, characterized in that, in order to increase the accuracy and automatic recording of the measurement results, additional multiple-frequency impulses synchronized by the reference signal are generated from the reference signal, compared to the pulses obtained from the test signal, and the desired value.

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