Sound and Vibration Instrument Hire and Calibration
Norsonic 118 Specifications
| Nor 118 Real Time Noise Meter - filters, statistics and level v time | £ 24 a day * |
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Overall Performance
Nor-118 is a sound level meter complying with: IEC 60651 type 1, IEC 60804 type 1 and IEC 61672-1 class 1, group X measuring exponential time-weighted levels, Integrating Sound Levels - Leq and sound exposure levels.
Dimensions:
(WxHxD)76 x 234 x 32 mm; 3 x 9.2 x 1.3 inches
74 x 365 x 32 mm; 3 x 14.4 x 1.3 inches with microphone/preamplifier
Weight: 630g; 1.4 lbs. with batteries
Analogue Inputs
Number of channels: 1
Input connector: 7 pin LEMO connector
Preamplifier supply voltage: ± 17 V, max 3 mA
Polarisation voltage: 0V and 200V, selectable.
Maximum input signal: 11 Vpeak
Input impedance: > 100 kohm and < 650 pF
Measurement range: 0.3 µV to 7 V (RMS) in one range corresponding to -10 dB to 137 dB with a microphone sensitivity of 50 mV/Pa. The maximum peak value ±10 V corresponds to 140 dB.
High pass filter
The input of the sound level meter is equipped with a high pass filter to reduce noise from wind or other sources with frequencies below the frequency range for measurements.
Filter type: 3rd order HP filter (-3 dB at 4 Hz, Butterworth response)
Analogue to digital conversion
The analogue input signal is converted to a digital signal by a multi-range sigma-delta converter with an effective sampling frequency of 48 kHz. The anti-aliasing filter is a combination of an analogue and a digital filter.
Spectral weighting
Simultaneous measurement of A- and Z- or C-weighting. Octave band or third octave band levels may be measured simultaneously if options providing these weightings are installed.
Octave filters: 8, 16,..., 16000 Hz, class 1 digital IIR filters, base 10 system. (IEC 61260).
One-third-octave filters: 6.3, 8, 10,..., 20000 Hz, class 1 digital IIR filters, base 10 system (IEC 61260).
Level detector
Detector type: Digital true root-mean-square (RMS) detection, resolution 0.1 dB which may optionally be increased to 0.01 dB for indicated levels in the range -9.99 to 99.99 dB.
Crest factor capability: The crest factor is only limited by the peak-value of the signal.
Simultaneous measurement of the following functions:
SPL, Lmax; Lmin; Leq; LE; Lpeak; Ln (the exceedance level for F-time-weighted sound pressure level, the cumulative distribution); LeqI; LEI; LTMax5.
Indication range
The calibration of the instrument allows microphones with sensitivity in the range -84 dB to +15.9 dB relative to 1 V/Pa to be applied. The corresponding display range for the indicated sound level is -50 dB to +180 dB.
Self-noise levels
The self-noise is measured with the calibration set to -26.0 dB corresponding to a microphone sensitivity of 50 mV/Pa. For voltage input the level 0 dB then corresponds to 1 µV. Typical values for the self-noise are 5 dB lower than values stated. Noise measured with 18 pF microphone dummy and microphone preamplifier Nor-1206, averaged over 30 s of measurement time:
A-weighted: 13 dB
C-weighted: 15 dB
Z-weighted: 25 dB
1/3 oct: 6.3 Hz to 250 Hz: 10 dB
1/3 oct: 315 Hz to 20 kHz: 5 dB
Power supply
Batteries: 4 cells, IEC Lr6, AA-sized, Alkaline batteries recommended (e.g. Duracell Ultra M3). AA-sized NiCd or NiMH rechargeable batteries may be used, but must be charged outside the instrument. Battery voltage and time on battery since last change of batteries are indicated.
Typical battery life time: 8 hours
External DC: 11--15 V. Power consumption approximately 1.4 W depending on selected modes of operation. External DC source should have an source impedance less than 1 W and be able to supply at least 300 mA. If the external supply falls below 9 V, the instrument will use the internal batteries if available. If the instrument switched itself off due to loss of power, it will automatically switch on and resume normal operation once external DC supply reappears.
Display
The display is a monochrome, trans-reflective LCD graphical display with 160x240 pixels (W x H) with automatic temperature compensation for contrast and viewing angle. Applied backlight switches off automatically 2 minutes after the last operation of any key. The bargraph display covers 80 dB which may be scrolled in 10 dB steps to cover the total range.
Analogue output
Max output voltage: ± 10 V
Output impedance: < 100 ohm. The output is short-circuit proof to ground.
Frequency response re. 1 kHz: ± 0.2 dB for 100 Hz < f < 5 kHz, ± 1 dB for 20 Hz < f < 20 kHz.
Serial I/O port: Rs232 port, 9600 to 115200 baud
Data storage
Measured data is stored in the internal memory of the sound level meter. The memory is of the "flash" type retaining the information without supply from any battery. Approximately 5 Mbyte is available for the data storage. This corresponds to one of the following examples:
More than 2,500 global measurements with all available global functions and distribution when octave and fractional octave analysis is active.
Approximately 2,500,000 samples of L(t) when only one function is logged, corresponding to more than 60 hours with a resolution of 0.1 sec.
More than 90,000 samples of L(t) when all 28 functions are logged in profile, corresponding to mote than 25 hours with a resolution of 1 sec.
Environmental conditions for operation
Temperature: -10 °C to +50 °C, max 15 °C/hour
Humidity: 5 to 90 % RH, dew point less than 40 °C
Atmospheric pressure: 85 to 108 kPa
Environmental condition for storage
Temperature: -30 °C to +60 °C, max 15 °C/hour
Humidity: 5 to 90 % RH, dew point less than 40 °C
Atmospheric pressure: 50 to 108 kPav
