Digitizer that we used in Passive Seismic Tomography

Motto:

Common sense…uncommon innovation

Digitizer

External Hard Disk

FEATURES

24-bit delta sigma A/D converter, 4th generation seismic recorder
3 or 6 channels
Events only telemetry available
Earthworm exporter

The SMART Series of instruments represent the logical solution for seismological data acquisition: a common design for a digitizer, portable recorder, and strong motion recorder

(the all-in-one solution).

The traditional difference between these instruments vanishes, a strong motion recorder can now simultaneously record continuously weak motion data on a large selection of media: up to 120 GB hard disks, Compact Flash memory, etc. All units are telemetry ready using the CD1.1 protocol.

Very low power consumption is supplemented by a complete set of serial and Ethernet communication ports. Theremovable hot-swappable enclosure has a USB2.0 port for very fast data download. A SEEDLink plug-in is also provided.

SMART-24 SERIES SPECIFICATIONS

DATA ACQUISITION

Number of inputs 3 or 6 channels
Input type Balanced differential with transient protection suitable for both passive and active sensors
Input range 5Vp-p, 20Vp-p and 40Vp-p bipolar differential, 2x1 Mohm
Gain Software selectable: x1, x2, x4, x8, x16, x32, x64
Common mode rejection Greater than 90 dB
Digitizer Over sampled 24-bit Delta Sigma ADC with digital signal processing, 1 per channel
Anti-alias filter Brickwall digital FIR filter, cutoff at 80% of and 130 dB down at output Nyquist frequency. Causal filter optional.
Dynamic range Up to 138 dB
Intermodulation distortion Less than –110 dB
Sample rates 1, 5, 10, 20, 40, 50, 100, 125, 200, 250, 500, 1000, 2000 sps primary sample rates
Noise ~1 count RMS at up to 200 sps

ACQUISITION MODES (SMART-24R® only)

Continuous User selected start time, ring buffer or until storage full
Timed 16 user programmable
recording windows
Triggered Threshold, STA/LTA (updating or non-updating), and external
Pre-event length Up to 32,768 data samples
Post-event length Up to remaining data storage
DATA STORAGE (SMART-24R® only)
On board memory 192 MB
Type Up to 120 GB hard disk, up to 64 GB industrial grade Compact Flash memory, subject to market availability
Recording format Standard FAT32 file system, drives readable directly on a PC, format converters available for 32-bit SUDS, SAC, SEG-Y, SEISAN, MatLab, miniSEED, CSS3.0 and SEED

INTERNAL RECORDING (ALL VERSIONS)

Two PC Card slots for Compact Flash or microdrives, having 1 or 2 partitions and accessible by any ftp client.
TIMING Voltage controlled TCXO with optional external GPS synch.
Accuracy <10 microseconds of UTC with GPS lock
Stability 0.5 PPM (when unlocked)
GPS duty cycle User programmable GPS power on/off cycle times

INTERFACES

Indicators Large graphic LCD, protected
Communications 2xRS232, Ethernet, USB2.0 for the removable enclosure
GPS Dedicated RS-422 serial port
Power Main power and external battery
Other I/O 5 or 8 12-bit analog inputs, external trigger in/out, 1 PPS in/out
Calibration Pulse, sine wave, white noise, random binary, step functions, and shorted input
Telemetry - CD1.1 protocol, 4 independent profiles to 4 different IP servers;
- 64MB internal buffer for backfill;
- continuous, events only or both