7
the events to be set-up in accordance with the natural daily variations in the residual (background) noise.
For each event the following information is stored at ½ or 1 second intervals:
– SPL and L
eq
values
– 1/3-octave spectrum, PNL (Perceived Noise Level) and PNLT (Perceived Noise Level, Tone Corrected)
values, according to ICAO Annex 16
– The sound file
Furthermore, EPN dB (Effective Perceived Noise Level) of all the events according to ICAO Annex 16 is
calculated and stored in the database.
All results can be downloaded to the central server provided with the supported central software (such as
Environmental Noise Management Software Type 7843) continuously, or viewed in real-time remotely
over a LAN or GPRS connection. With Noise Monitoring Software Type 7802, results can be downloaded
via the optional modems to supported central software at a user-defined time interval, for example, once
per day.
Sound Recording
Noise events can be recorded for later analysis or source identification (for Type 3639-A-, -B- or -E-200
series configurations, Event Analysis Software BZ-7844 is required). The files are stored as a compressed
file (MP3) reducing the time and load spent on downloading data from the NMT. Alternatively, the
recordings can be stored as high-fidelity wav files for post-processing, such as tone analysis using FFT in,
for example, PULSE™ LabShop. If desired, sound recording can instead be done at regular, user-defined
times. This enables the NMT to record sound at user-defined time intervals and durations for, for example,
1-minute sound recordings to be made at the start of every one hour in order to identify typical sound
environments.
Meteorological Data
With optional Weather Station MM-0256 installed, temperature, windspeed and direction, relative
humidity, air pressure and liquid precipitation can be monitored. Alternatively, a two-parameter Weather
Station MM-0316 for windspeed and direction can be installed. The external weather station, mounted for
example on a mast, is connected via a serial interface to the NMT’s System Controller. The station is
delivered with a license to run the weather-data logging software needed to store the weather data in the
NMT’s own database in the same manner as the noise measurements.
GPS Geographical Positioning
The NMT supports GPS so that, together with a standard commercial GPS receiver and antenna unit (for
example, GPS Receiver with Antenna ZZ-0249), position (longitude, latitude and height) can be monitored
and stored in the NMT’s own database in the same manner as the noise measurements.
Camera Support
The NMT can be configured to support an outdoor camera (for example, Outdoor Camera WQ-2837) so
that pictures can be taken at 1 s intervals during noise events. You can set up the maximum number of
pictures saved per event. This helps identify the causes or even individual offenders of the noise events
and ensures that the amount of data stored is optimised to give enough detail while limiting the amount
of data to be transferred and stored.
Communication, Analysis and Reporting
The NMT can communicate with a range of software, depending on the configuration selected, see Table
1 and Table 2.
The ‘200’ series NMTs can be controlled remotely by Environmental Noise Management Software Type
7843 or ANOMS airport noise monitoring software, via standard internet-based protocols such as LAN or
GPRS, as it is given an IP address. The NMT continually streams the data required by the ENM/ANOMS
software user to the system server while storing it locally on the NMT as backup. Transmission of data is
performed simultaneously with data logging, without data loss. Analysis and reporting of results are done
using Environmental Noise Management Software Type 7843, or ANOMS airport noise monitoring
