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› Mae 29
VIBRALOG
SUPPORTED INVESTIGATION
Passive seismic acquisition
Seismic vibration monitoring
Nakamura method
mae-srl.it/go/vibralog
24 bit seismograph for passive seismic
activity, particularly indicated
for recording micro-earthquakes or
seismic vibrations. The data acquisition
methods (timed or with trigger
threshold) are set through the software
easily and quickly. Equipped
with graphic display, keyboard, memory
support of Secure Digital (S.D.)
type and internal battery, seismograph
VIBRALOG is particularly easy
to use also in less favourable environments
and conditions.
Thanks to the MAE data acquisition
and conversion card, based on one
single A/D signal converter for each
inlet channel (SST technology), it allows
to obtain the best possible resolution
when acquiring the data for
each single inlet channel and it allows
to record and graphically visualize
up to 4 channels coming from
seismic sensors (with single component
or tridimensional).
Thanks to its dynamic characteristics,
the instrument is particularly
suitable to determine the resonance
frequency of the site, through
the H/V ratio method and to acquire
transitional events (caused by natural
seismicity or human activities)
with the purpose to calculate the
maximum speeds of the stresses suffered
by a structure.
SPECIFICATIONS
• Converters: 24 bit resolution, sigma- delta
technology
• Dynamic range: 144 dB (theoretical)
• Maximum distortion: +/-0.0010%
• Band width: 2Hz-30KHz
• Common mode rejection: 110dB at 60Hz
• Diaphony: -120dB at 20Hz
• Noise threshold of the programmable amplifier:
27nV
• Maximum range of inlet signal: +/-5V
• Inlet impedance at 1000 samples/second:
20MΩ
• Amplification levels: 0dB, 6dB, 12dB, 18dB,
24dB, 30dB, 36dB that can be set singularly
for each channel
• Anti-alias filter: -3dB, 80% of Nyquist frequency,
-80dB
• Pre-trigger time: from 1% to 50% of the event
duration
• Sampling frequencies 100, 500, 1000, 2000
samples per second; 250c/s in continuous recording
• Sampling intervals: 0.5, 1.0, 2.0, 4.0, 10.0 ms
• Length of the event recorded: from 512 to
21504 samples (215sec. at 100c/s or 10.7sec.
at 2000c/s). Depending on SD capacity in continuous
recording
• Delay: not available
• Channels: 3 + 1 optional. Possibility to use
from 1 to the maximum number of channels
installed for each acquisition
• Test on instruments: only in the laboratory.
Internal self-calibration of the converters prior
to each acquisition
• Digital filters: selected automatically based
on the sampling frequency
• Data storage: on removable SD memory, up
to 2 GB
• Trigger: 10 threshold levels for each channel
(minimum 8mV – max. 5V). Up to 3 coincidence
combinations between channels
• Data format: SEG-2 standard (32-bit long integer),
BIN convertible in ASCII
• Power supply: 12V DC. Internal batteries of
2.5Ah. Average absorption: 150mA.
• Environmental conditions: -20/80°C
• Display: mono-chromatic graphic LCD 320 x
240 pixel
• Keyboard: 6 charge-transfer buttons
• Sizes: 23.8 x 6.7 x 14.1 cm
• Weight: 1.4 Kg (cables and sensors excluded)