Guralp Systems Limited
MAN-C3E-0002 - Güralp 3ESPCD Digital Broadband Seismometer (DM24 Versions) - Users' Guide

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1. Preliminary Notes 2. Introduction 3. Installing the 3ESPCD 4. Calibrating the 3ESPCD 5. Using Scream! 6. Command line interface 7. Inside the 3ESPCD 8. Appendix A - Connector pin-outs 9. Appendix B - Sensor Specifications 10. Appendix C - Digitiser specifications 11. Revision History

Chapter 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

Absolute accuracy

0.5% standard (0.1% optional)

Type

5th-order, single-bit low-pass noise shaper

Analogue transducer outputs

3-C signals

Clock

Oscillator

8×10–7 standard (5×10–8 oven-controlled optional)

External receiver interface

GPS RS232 and PPS

External receiver synchronisation

<50 µs

Power

Supply

+10 – +36 V DC

Current at 12 V DC

~0.12 A

PreviousNext

1. Preliminary Notes 2. Introduction 3. Installing the 3ESPCD 4. Calibrating the 3ESPCD 5. Using Scream! 6. Command line interface 7. Inside the 3ESPCD 8. Appendix A - Connector pin-outs 9. Appendix B - Sensor Specifications 10. Appendix C - Digitiser specifications 11. Revision History