Guralp Systems CMG-3ESPCD - Manual (Page 96)

CMG-3ESPCD Digital Broadband Seismometer Appendix C - Digitiser specifications
10 Appendix C - Digitiser specifications
Seismic channels Number 4
Format 32 bit
Inputs Differential with transient
protection; ±10 V input
range
Input impedance 1 MΩ, 10 nF
Common mode rejection 110 dB at 10 Hz
Mux channels Number 8
Format 24 bit
Inputs Single ended; ±10 V input
range
GPS Unit External GPS (CMG-GPS2)
Power Via GPS connector
Time format NMEA
Max. cable length 50 m
Sensor control Functions available Lock, unlock, and centre
sensor; enable calibration
Sensor calibration Types Sine and square wave,
adjustable amplitude and
frequency; broadband noise,
adjustable amplitude
Digital signal
processing
Type Texas TMS320CV33
Hardware sampling rate 512 KHz
Sample output rates
6 cascaded rates, each 2, 4, or
5 times lower than the
previous rate
Anti-aliasing filters 2 pole
Low-pass filters FIR
Out-of-band rejection 140 dB
In-band ripple –140 dB
Trigger modes STA/LTA, level, external
Digitiser
performance
Output format 32 bit
Noise-free resolution
(NPR)
22.5 bits at 20 samples/s
21.5 bits at 100 samples/s
MAN-C3E-0002 96 Issue B - November 2013