Technical Specifications - Gecko Compact Product User Manual

Technical Specifications

Analogue to Digital Converter:
Input (most models)
Pre-gain sensitivity (gain x1 to x4):
Pre-gain sensitivity (gain x1 to x4):
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):
Data Format:
Frequency Response:
*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 Apply Gecko
FIR Filtered FIR filter
250 YES
500 YES
1000 YES
250
2000 YES
500
4000 YES
1000
2000
4000
32-bit ADC Rate FIR Filter Coefficients
SESSION 1 SESSION 2
1/512 1/8388608
1 3
2 0
3 -25
4 0
5 150 -507,903
6 256
7 150 2,512,192
8 0 4,194,304
9 -25 2,512,192
10 0
11 3 -507,903
12
13
14
15
32-bit ADC on each channel
40V peak to peak (at gain x1)
457,000* counts per volt (to serial #2000224)
406,000* counts per volt (from serial #2000225)
280,000* counts per volt (all serial numbers)
MiniSEED with STEIM-1 compression
Stored as 24-bit number (±8,388,608 counts)
Flat from DC to ~40% of sampling frequency
Decimation
/5
/5
/5
/5
/5
SESSION 3
134,217,728
-10,944 0
0 0
103,807 -73
0 -874
-4,648
0 -16,147
-41,280
-80,934
-120,064
0 -118,690
-18,203
0 224,751
103,807 580,196
0 893,263
-10,944 891,396
24-bit Output Rate
50
100
200
250
400
500
800
1000
2000
4000
SESSION 4
134,217,728
-132
-432
-75
2,481
6,692
7,419
-266
-10,663
-8,280
10,620
22,008
348
-34,123
-25,549
33,460
26
Band
Code
B
H
H
C
C
C
C
F
F
F
Gecko FIR Filter
-0.00000000603039587567231
0.00000003927395595069500
0.00000015049773405261000
0.00000031773952781082800
0.00000047798502203373000
0.00000051095157690769800
0.00000026641905055507000
-0.00000037216765923750700
-0.00000139966508074817000
-0.00000260778978135591000
-0.00000355477433765434000
-0.00000362926632635530000
-0.00000222929759367356000
0.00000096520518738636800
0.00000569997133939469000
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15