Hluk merače - environmentálne testovanie
Hluk merače, tiež známy as (hluk merače, zvuk hladina merače) are *základné* nástroje pre hluk meranie. A zvuk úroveň meter je všeobecne zložený zložený z z a kondenzátor mikrofón, a predzosilňovač, an útlm, an zosilňovač, a frekvencia meter sieť, a an RMS indikátor hlava. The pracovný princíp z a zvuk hladina meter je: mikrofón konvertuje the zvuk na an elektrický signál, a potom the predzosilňovač transformuje the impedancia so to the mikrofón zhoduje the atenuator. The zosilňovač pridáva the výstup signál do sieť, závažia the signál pre frekvenciu počítanie (alebo externý filter), a potom zosilňuje signál do na a a určitý amplitúda by the ttenuator and zosilňovač, a odosiela it do na the RMS detektor.
Hluk merač Princíp �
The frequency weighting network in the noise meter has three standard weighting networks, A, B and C. The A network simulates the response of the human ear to the 40-square pure tones in the equal-loudness curve, and the shape of its noise meter curve is opposite to the equal-loudness curve of the 340-square, which results in greater attenuation in the middle and low frequency bands of the electrical signal.The B network simulates the response of the human ear to the 70-square pure tones, and results in a certain degree of attenuation in the low-frequency band of the electrical signal.The C network simulates the response of the human ear to the 100-square pure tones. The C network simulates the response of the human ear to a 100-square pure tone, which has a nearly flat response over the entire frequency range. The sound pressure level measured by a sound level meter through a frequency weighting network is called the sound level, and according to the different weighting networks used, it is called the A sound level, B sound level and C sound level, and the units are recorded as dB(A), dB(B) and dB(C). At present, the measurement of noise with a sound level meter, the meter head response according to the sensitivity can be divided into four kinds:
1, "slow". Meter head time constant of 1000ms, - generally used to measure steady state noise, the measured value for the effective value.
2. "Fast". The time constant of the meter head is 125ms, ktorý je všeobecne použitý na na meranie the large fluktuation of unsteady noise and transportation noise. Fast gear is close to the human ear's response to sound.
3. "Pulz alebo pulz držanie". The rise time of the meter needle is 35ms, ktorý je použitý na na merať the impulzný šum s dlhší trvanie, such as dierovanie stroj, lisovanie kladivo, atď. The measured value is the larger RMS value.
4. "Peak Hold". The rise time of the meter needle is less than 20ms, used to measure the impulse sound of short duration, such as guns, cannons and explosions, the measured value is the peak value. That is, the * big value.
Sound level meter can be connected to external filters and recorders, to do spectrum analysis of noise. Domestic ND2-type precision sound level meter equipped with an octave page range filter, easy to carry to the scene and for spectrum analysis. Sound level meter can be divided into precision sound level meter and common sound level meter according to the accuracy. The measurement error of the precision sound level meter is about 1dB, and that of the ordinary sound level meter is about 3dB. The sound level meter can be divided into two categories according to its use: one is used to measure steady state noise, and the other is used to measure unsteady state noise and impulse noise. Integral sound level meter is used to measure the equivalent sound level of unsteady noise over a period of time. A noise dosimeter is also an integrating sound level meter and is primarily used to measure noise exposure. Impulse sound level meter is used to measure impulse noise, this kind of sound level meter conforms to the response of the human ear to impulse sound and the average time of the response of the human ear to impulse sound.
Noise Meter-Standard Requirements
