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Geode
Portable Seismograph Module Specifications
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A/D
Conversion: 24
bit result using Crystal Semiconductor sigma-delta
converters and Geometrics proprietary oversampling.
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DynamicRange:
144
dB (system), 110 dB (instantaneous, measured) at 2ms,
24dB.
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Distortion:
0.0005%
@ 2 ms, 1.75 to 208 Hz.
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Bandwidth:
1.75
Hz to 20 kHz. Low corner frequency option available.
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Common
Mode Rejection: >
-100 dB at <=100 Hz, 36 dB.
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Crosstalk:
-125
dB at 23.5 Hz, 24 dB, 2 ms.
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Noise
Floor: 0.2uV,
RFI at 2 ms, 36 dB, 1.75 to 208 Hz.
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Stacking
Trigger Accuracy: 1/32
of sample interval.
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Maximum
Input Signal: 2.8
VPP.
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Input
Impedance: 20
kOhm, 0.02 uf.
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Preamplifier
Gains: SGOS
software enables selectable gain pair of either 24 or
36 dB. MGOS software selection between jumpered gain
pair 12 and 24 dB, gain pair 24 and 36 dB, or 0dB.
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Anti-alias
Filters:
-3 dB at 83% of Nyquist frequency, down 90 dB.
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Pre-trigger
Data:Up
to 4,096 Samples. Optional event detection software
enables system for earthquake, vibration monitoring.
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Sample
Interval:0.02,
0.3125, 0.0625, 0.125, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0,
16.0 ms.
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Record
Length: 16,000
samples standard, 64,000 samples optional 2
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Delay:
0
to 9999 ms in 1 ms steps.
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DataTransmission:Uses
reliable Ethernet connections and requires no custom
transmission software. Interfaces directly with
network capabilities of Windows 95/98/NT.
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AuxiliaryChannels:
All
Geode channels can be programmed as either AUX or DATA.
Fixed data aux channels available in StrataVisor DZ.
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Instrument
Tests:Optional
built-in daily, weekly and monthly testing available.
External laboratory quality oscillator available to
measure noise, crosstalk, dynamic range, gain similarity
and trigger accuracy to factory specification
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Acquisition
and DisplayFilters:
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LowCut:OUT,
10, 15, 25, 35, 50, 70, 100, 140, 200, 280, 400 Hz,
24 or 48 dB/octave, Butterworth.
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Notch:50,
60, 150, 180 Hz and OUT, with the 50 dB rejection
bandwidth 2% of center frequency.
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HighCut:OUT,
250, 500 or 1000 Hz, 24 or 48 dB/octave.
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LineTesting:
Real
time noise monitor displays real-time output from
geophones. Optional geophone pulse test helps identify
bad geophones and shorted or broken cables.
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Data
Storage: Stores
data locally on laptop hard drive for transfer to
portable media . Additional tape options available. 2
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Triggering:
Positive,
negative or contact closure, software adjustable threshold.
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Data
Formats: SEG-2
standard with SGOS. SEG-D and SEG-Y available. 2
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Power:Requires
12V external battery. Uses 0.65 W/channel during acquisition,
sleep mode reduces power consumption by 70% while in standby.
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Plotters:Drives
a variety of NT compatible printers including Printrex 4, 8
and 12 inch plotters. Consult factory.
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Environmental:
-30
to 75 degrees C. Waterproof and submersible. Withstands a 1 m
drop onto concrete on 6 sides and 8 corners.
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Operating
System: Windows 95/98/NT.
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Notes:
Laptop
computers are NOT field devices! They are easily damaged by harsh
treatment or exposure to extreme environments. They have a
short battery life. Geometrics StrataVisor NZ is designed to operate
in harsh conditions for extended periods and should be used with the
Geode for professional surveys when reliability is important.
Additional
with MGOS software. |
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