Testo testo 815 Sound level-measuring apparatus, Noise-measuring apparatus 0563 8155 用户手册
产品代码
0563 8155
27
Absolute pressure dependency
testo 815 is calibrated by default for measurements at a height of
0 m above sea level. Measurements at other heights give rise to
measurement errors which can be corrected using a table (see
technical data). Subtract the appropriate offset value from the
value measured (e.g. - 0.1 dB for measurements at a height of
500 m above sea level). You can avoid this measurement error by
calibrating the meter in the corresponding height prior to every
measurement. Please refer to the Instruction Manual for the
calibrator.
testo 815 is calibrated by default for measurements at a height of
0 m above sea level. Measurements at other heights give rise to
measurement errors which can be corrected using a table (see
technical data). Subtract the appropriate offset value from the
value measured (e.g. - 0.1 dB for measurements at a height of
500 m above sea level). You can avoid this measurement error by
calibrating the meter in the corresponding height prior to every
measurement. Please refer to the Instruction Manual for the
calibrator.
Wind cap
Generally the wind cap supplied should be attached during
measurements outdoors and when air movements occur. Wind
noises in the microphone cause measurement errors since the
wanted signal (of the noise source) and the wind noise add up
together.
Generally the wind cap supplied should be attached during
measurements outdoors and when air movements occur. Wind
noises in the microphone cause measurement errors since the
wanted signal (of the noise source) and the wind noise add up
together.
The wind cap does not falsify the measurement result.
Overmodulation and undermodulation
With every measurement cycle, the sound level meter checks
whether the measured sound level is in the validity range of the
respective measurement range. Deviations are indicated by
"Over" and "Under" on the display. However, the criteria for
overmodulation and undermodulation are different.
Overmodulation is signalled if the maximum value (peak value e.g.
short sound pulse, bang) during the last measurement cycle was
too high. This value may be considerably higher than the actual
value of the sound level displayed. Therefore, it can happen that
"Over" is signalled although a sound level within the normal
framework of the respective measurement range is shown. By
contrast "Under" is geared to the measured actual value and is
therefore set when the lower limit of the measurement range is
reached.
With every measurement cycle, the sound level meter checks
whether the measured sound level is in the validity range of the
respective measurement range. Deviations are indicated by
"Over" and "Under" on the display. However, the criteria for
overmodulation and undermodulation are different.
Overmodulation is signalled if the maximum value (peak value e.g.
short sound pulse, bang) during the last measurement cycle was
too high. This value may be considerably higher than the actual
value of the sound level displayed. Therefore, it can happen that
"Over" is signalled although a sound level within the normal
framework of the respective measurement range is shown. By
contrast "Under" is geared to the measured actual value and is
therefore set when the lower limit of the measurement range is
reached.
5. Operation
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