The sound represents fluctuations of any given environment. Air, water or other substance capable to transfer longitudinal waves can be such environment. To a sound of any given height there corresponds a certain number of fluctuations. Acoustics is engaged in measurements of parameters of a sound. Need to measure the frequency of fluctuations quite often arises also in life at setup of various devices, from musical instruments to internal combustion engines.
It is required to you
- - sensitive microphone;
- - frequency meter;
- - oscillograph;
- - tuning fork:
- - otgraduirovanny sound generator;
- - amplifier of low frequency.
Instruction
1. The most available method is to measure frequency on a frequency meter. Connect to it the microphone and bring to a sound source. On a scale of a frequency meter look, you received frequency what sound. If the level of a signal is insufficient for measurement, strengthen it by means of the electronic amplifier of sound frequency.
2. If the frequency meter near at hand does not appear, measure the frequency of fluctuations by means of an oscillograph and the sound generator. At the same time connect a chain of the microphone and amplifier of sound frequency to one of couples of plates of an oscillograph (for example, Y), and the output of the sound generator - to other couple of plates, that is X.
3. Include a collected chain of devices and determine the frequency of a sound signal by Lissazhu's figures on the oscillograph screen. At the same time it is possible to use the settings of strengthening which are available in an oscillograph and if those are, dividers and frequency multipliers.
4. All stated methods are based on transformation of a sound signal to electric. But there is also older checked method of determination of sound frequency by means of a tuning fork. If a sound rather loud, then a tuning fork leg just strictly fix to a sound source. Displace a moving crossing point on divisions so that there was the maximum vibration of short moustaches of the device. Determine frequency by divisions of the scale applied on one of mustache. The ancient classical tuning fork with a moving crossbeam is necessary for such experience. The devices intended for control for certain notes for measurement of unknown sound frequencies are unsuitable.
5. For measurement by a kamertonny method of frequency of weaker sounds the device is equipped with special resonators in the form of bells, boxes, etc. They are done of a tree or metal. The same resonators are used to measurement of sounds from the remote sources.
6. By the same principle, as a tuning fork, the string measuring instrument of frequency of a sound works. It has the second name - monochords. In this case the crossing point with the index of frequency moves along the tense string, and the scale is applied on the device bed. Monochords gives the big accuracy, than a tuning fork. But it demands obligatory control and checking just before measurement.