CMG-DM24 3- to 12- channel broadband digitizer

  The Guralp CMG-DM24 is a high-quality digitizer with full 24-bit resolution, designed for data quality and durability with models available for 3, 6, 9, or 12 channel recording.

 

  Features

 

  • 4 low-noise 24-bit ADCs (expandable to 7, 14)
  • Fourth channel for user signals and calibration
  • 8 environmental channels with 20-bit resolution (3 x mass position, 5 user)
  • Low power 32-bit DSP and ARM processor (<1 W recording 4 channels at 100 sps)
  • Multiple concurrent data rates up to 1000 sps
  • STA/LTA, ratio, external and software triggering
  • Triggered and continuous streams output simultaneously
  • Event selection and download over data port
  • Full control of Guralp broadband sensors including remote lock, unlock and centre
  • Calibration using step, sinusoid or pseudorandom broadband noise signals
  • Remotely configurable using Guralp data modules and software
  • UTC timestamped data using low power GPS
  • Up to 8 Gb Flash storage (64 Mb standard) with FireWire transfer
  • Multiple storage and transmission modes
  • Built-in modem support
  • Available in surface, borehole and integrated packages or as a retrofit to existing sensors for instant digital seismic stations

 




  Specifications
Signal channels 3, 6, 9, 12 @ 24 bits
Auxiliary/ calibration channels 1, 1, 2, 2 @ 24 bits
Input voltage range (surface) ±10 V (±20 V optional) differential
Input impedance (surface) 1MQ /10 nF
Inputs (borehole and integrated) matched to sensor
Environmental channels 8 @ 4 samples/s, 16-bit resolution
Environmental channel range ±10 V single-ended
ADC converter type 5th-order single-bit low pass AX
Output format 24-bit (32-bit low-noise option)
Dynamic range 137dB (141dB) @ 40 samples/s
Absolute accuracy 0.5% (0.1%)
Common-mode rejection 120 dB@ 10 Hz
DSP sampling rate 32 kHz
Output rates available 1000 .. 1 samples/s
Highest output capability 3 channel: 3 x 1000 + 1 x 500 6 channel: 3 x 1000 + 4 x 500
Decimation filters 2, 4, 5, 2x4, 2x5
Anti-alias filters 3-pole
Low pass filters FIR (other options available)
Out-of-band rejection 140 dB
In-band ripple -140 dB
DSP trigger modes STA/LTA, level, external, software
Timing source precision 8 E-07
Optional precision RTC 1.7 E-08 (30 mW power cost)
Calibration signal generator Amplitude/frequency adjustable sine wave, step or broadband noise
Flash storage
 64Mb (options to 8 Gb)
Sensor control commands Remote lock, unlock, centre
Optional smart sensor interface SSI l²C/l-wire interface
Operating temperature -40 to +60 °C
Power supply 12 36 V DC

Current at 12 V DC

 3 channel: 77 mA = 0.92 W
6 channel: 120 mA - 1.44 W
GPS: 35 mA - 0.42 W