Εισαγωγή και Χρήση του Θόρυβος Μέτρα
A θόρυβος μετρητής, επίσης γνωστό ως a θόρυβος μετρητής ή ήχος επίπεδο μέτρο, is a basic όργανο in θόρυβος μέτρηση. A ήχος στάθμη μέτρο γενικά αποτελείται από a χωρητική μικρόφωνο, προενισχυτής, εξασθενητής, ενισχυτής, συχνότητα μετρητής δίκτυο, και αποτελεσματικός τιμή δείκτης κεφάλι. The working principle of a sound level meter is that the microphone converts sound into electrical signals, and then the preamplifier transforms impedance to ταίριασμα το μικρόφωνο με το εξασθενητής. ο ενισχυτής προσθήκες το έξοδος σήμα στο δίκτυο, performs συχνότητα στάθμιση (ή εξωτερικό φίλτρο) on the σήμα, και τότε amplifies the σήμα to a βέβαιο πλάτος μέσω το εξασθενητής και ενισχυτής, αποστολή it to the effective value ανιχνευτής.
Αρχή του θόρυβος μετρητής
There are three standard weighting networks in noise meters: A, B, and C. The A network simulates the response of the human ear to a 40 square pure tone in the equivalent response curve. Its noise meter curve shape is opposite to the 340 square equivalent response curve, resulting in significant attenuation in the middle and low frequency bands of the electrical signal. The B-network simulates the response of the human ear to 70 square pure tones, which attenuates the low-frequency range of electrical signals to a certain extent. The C network simulates the response of the human ear to 100 square pure tones, with a nearly flat response throughout the entire audio frequency range. The sound pressure level measured by the sound level meter through a frequency weighting network is called the sound level. Depending on the weighting network used, it is called the A sound level, B sound level, and C sound level, with units recorded as dB (A), dB (B), and dB (C). At present, the sound level meters used for measuring noise can be divided into four types based on sensitivity:
1. Αργή. Ο χρόνος σταθερά του το μετρητής κεφαλή is 1000ms, που είναι γενικά χρησιμοποιείται για μέτρηση σταθερή κατάσταση θόρυβος, και το μετρούμενο τιμή είναι το αποτελεσματικό τιμή.
2. Γρήγορο. Ο χρόνος σταθερά του του μετρητή κεφάλι είναι 125ms, που είναι γενικά χρησιμοποιείται για μέτρηση ασταθής θόρυβος και μεταφορά θόρυβος με σημαντικές διακυμάνσεις. Ο γρήγορος γρανάζι προσεγγίσεις ο άνθρωπος αυτί's απόκριση σε ήχος.
3. Pulse or pulse hold. The rise time of the watch needle is 35ms, used to measure pulse noise with a longer duration, such as punching machines, press hammers, etc. The measured value is the maximum effective value.
4. Peak Hold. The rise time of the watch needle is less than 20ms. Used to measure pulse sound with a short duration, such as guns, guns, guns, and explosions, the measured value is the peak value, which is the maximum value.
The sound level meter can be connected to an external filter and recorder for spectral analysis of noise. The domestically produced ND2 precision sound level meter is equipped with an octave bandpass filter, which is easy to carry to the site and perform spectral analysis. Sound level meters can be divided into precision sound level meters and ordinary sound level meters based on accuracy. The measurement error of a precision sound level meter is about 1dB, while that of a regular sound level meter is about 3dB. Sound level meters can be divided into two categories according to their purpose: one is used to measure steady-state noise, and the other is used to measure unstable noise and pulse noise. An integral sound level meter is used to measure the equivalent sound level of unstable noise over a period of time. A noise dosimeter is also an integral sound level meter, mainly used to measure noise exposure. Pulse sound level meters are used to measure pulse noise, which correspond to the response of the human ear to pulse sound and the average time of the human ear's response to pulse sound.
