Gecko Compact - Technical Specifications

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Technical Specifications
Analogue to Digital Converter: 32-bit ADC on each channel
Input (most models) 40V peak to peak (at gain x1)
Pre-gain sensitivity (gain x1 to x4): 457,000* counts per volt (to serial #2000224)
Pre-gain sensitivity (gain x1 to x4): 406,000* counts per volt (from serial #2000225)
Pre-gain sensitivity (gain x8 to x512): 419,430* counts per volt (all serial numbers)
Input (Pro model SMA-HR, Prism) 60V peak to peak (at gain x1)
Pre-gain sensitivity (gain x1 to x64): 280,000* counts per volt (all serial numbers)
Data Format: MiniSEED with STEIM-1 compression
Stored as 24-bit number (±8,388,608 counts)
Frequency Response: Flat from DC to ~40% of sampling frequency
*Nominal ‡See our website to download the Gecko Data Sheet for full technical specifications for each model
Sampling and Linear Phase Filter Stages & Coefficients – v6.0
Previous Gecko firmware used more complicated up-sampling, decimation and a longer
string of FIR filter coefficients. Gecko v6 has the same simpler floating point FIR filter as
used the Kelunji EchoPro, and only uses factor 5 decimation for non-native sample rates.
32-bit ADC Rate
FIR Filtered
Apply Gecko
FIR filter
Decimation
24-bit Output Rate
Band
Code
250
YES
/5
50
B
500
YES
/5
100
H
1000
YES
/5
200
H
250
250
C
2000
YES
/5
400
C
500
500
C
4000
YES
/5
800
C
1000
1000
F
2000
2000
F
4000
4000
F
32-bit ADC Rate FIR Filter Coefficients
Gecko FIR Filter
SESSION 1
SESSION 2
SESSION 3
SESSION 4
1/512
1/8388608
134,217,728
134,217,728
1
3
-10,944
0
-132
-0.00000000603039587567231
1
2
0
0
0
-432
0.00000003927395595069500
2
3
-25
103,807
-73
-75
0.00000015049773405261000
3
4
0
0
-874
2,481
0.00000031773952781082800
4
5
150
-507,903
-4,648
6,692
0.00000047798502203373000
5
6
256
0
-16,147
7,419
0.00000051095157690769800
6
7
150
2,512,192
-41,280
-266
0.00000026641905055507000
7
8
0
4,194,304
-80,934
-10,663
-0.00000037216765923750700
8
9
-25
2,512,192
-120,064
-8,280
-0.00000139966508074817000
9
10
0
0
-118,690
10,620
-0.00000260778978135591000
10
11
3
-507,903
-18,203
22,008
-0.00000355477433765434000
11
12
0
224,751
348
-0.00000362926632635530000
12
13
103,807
580,196
-34,123
-0.00000222929759367356000
13
14
0
893,263
-25,549
0.00000096520518738636800
14
15
-10,944
891,396
33,460
0.00000569997133939469000
15