Theoretical bases of a quality monitoring. Vibroacoustik the information from own vibrations bells products on the character carries relaccions character. At the description of this information in time it is possible to allocate the following periods of life Vibroacoustik information:
Where - wavlet in time:
, ms; - the maximal peak values of frequencies.
Where - wavlet in time:
, ms; - peak values of frequencies, including already are available frequencies, characteristic for the following period.
Steady realization- :
Where - вейвлетпреобразование in time:
, ms; - the maximal peak values of frequencies, which peak values were less in previous period, are maximal in this period and will decrease in the following period.
Where - wavlet in time:
, ms; - peak values of frequencies, which peak values were maximal in previous period and fade in this period.
In each period on wavlet-transformation frequencies dominant on amplitude are defined and factors are analytically defined frequency:
Where , Hz.
For cases when , it is defined(determined) as:
Where - an integer; - frequency at which is not observed expression for . Further, using the classification table vibroacoustiks2, on the received factors sound characteristics, and also an estimation of combinations of frequencies dominant on amplitude in the basic periods of life vibroacoustic information are defined.
Proceeding from these data the control of sounding bell products will be carried out.
Essence of a method. Sounding bell products is organically enough poured in in the natural environment, thus bears also emotional sense. Sounding bell transfers products certain adjust and are the factor of influence.
The quality monitoring of sounding bell products is constructed that vibroacoustic the information from own vibrations of a body radiated in an environment can be fixed and then to subject wavlet-transformation which shows development to this information in three planes: time, frequency and peak. On values of frequencies dominant on amplitude in each period the control of sounding of a product is conducted.
The general principles of allocation of the information and decided problems. Among the limited set of representation wavlet-transformations in work it is used two-dimensional wablet in which third parameter - the amplitude, - is shown by color with digital illumination. On color and digital peak values wavlet-strips dominant frequencies are defined. Then vibroacoustic the information, it is usual on is exposed to the multiwindow spectral analysis with specification of dominant frequencies on peak and frequency to values. Having received the exhaustive information on dominant peak values of frequencies, further on (5)factors are analytically defined(determined) frequency.
Criteria and technique of a choice of rational parameter for the control. The received factors allow to continue the analysis researched vibroacoustic information by sound criteria that allows to define a place vibroacoustic information in classification system vibroacoustics images. The estimation of combinations of frequencies dominant on amplitude in the basic periods of life vibroacoustic information with application frequency factors further is given. In conclusions of a method all received results are marked. Proceeding from these data, sounding bell products is characterized. According to the circuit rice 1 at the control fixed on bellchurch bell products the second microphone is removed from a bell and there is at height of 1 m from the ground. This level corresponds to a level of perception of sounding bell products the average student. The second microphone is used for the control of sounding bekk products in a zone of the average student and the control of correctness of a choice of height of fastening bell products. Thus, bell the product is removed from the average student on some distance. What it gives? , received from record of a sound from the first microphone which is taking place near to a controllable product, were, as a rule noise which will overcome the distance equal:
, M (7),
Where - speed of a sound, м/s, decreasing depending on height above the Earth.
If bell the product was at height of 1 m above the Earth to protect the average student from initial noise it would be required to remove bell a product on tens meters. This problem ancient masters intuitively solved with the help of removal bell products in heigt, placing it on bellchurch.
Thus, knowing the value , received from a microphone - 1 for bell products, the temperature changes of environmental natural environment increasing speed of a sound at its increase, it is possible to calculate minimally allowable height of fastening bell products on bellchurch with the purpose of improvement of quality of a sound for the average student or to recommend construction колокольни in view of results of the control of sounding bells products. For already constructed bellchurchs it is possible to solve a return problem: to expect the allowable values , a sound received at fixing at a product, and for them to select bells products. The microphone - 2 allows to supervise changes in , received with record from the second microphone. At absence in it of the noise which have been removed from a microphone - 1, it is possible to prove a choice of a place of fastening of a product experimentally. At researches bell products from new materials (an alloy of the professor Sil'mana G.I.) At the control of sounding micromelodies - that is the smooth directed frequency changes in time of the basic sound frequencies were revealed in .
Thus, the developed method of definition of sounding bells products allows:
1. to conduct the analysis of change of frequencies of a product in a time scale;
2. to allocate phases of life vibroacoustic information;
3. to reveal from a spectrum frequencies dominant on amplitude.
4. to conduct a classification estimation of sounding;
5. to conduct an estimation of combinations of frequencies;
6. to reveal micromelodies in a timbre of a sound;
7. to define height of fastening колоколообразных products above the Earth with the purpose of improvement of quality of perception of sounding;
8. to select on bells for constructed bellchurch;
9. to supervise quality of moulding bell products on sounding.
Complex of means of the control. The hardware of the monitoring system of sounding bell products in view of features of objects of the control is submitted on rice 1 and consists from: two microphones, one of which is put on distance of 20 sm from bell a product which are taking place, as a rule, on bellchurch, and the second at height of 1 m from the ground (in the field of a presence of the average student), two noutbooc with the card having ACP.
The software: a program digital oscillograph, program spectralanaliz and wavlet-converter.