Digital data recording

Digital acquisition (72 db dynamical range, sampling rate 1 kHz, 14 bit DAC, was performed by two (Fig.14) Intel based PC workstations SNSP2001/MC designed by NSTU. The software is able to digitize and write data in the SEG-Y format, while presenting the user the real-time data for control and QC (seismic trace, bottom profile, amlitude spectra etc). Fig.17 gives examples of the data acquisition windows on the workstation.

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Figure 17: Data Acquisition windows on digitizing workstation.

Main parameters for digital seismic station SNSP2001/MC.

• Gain control.
  • Input for seismic signal: differential or simple.
  • Input signal: >100mV, R-input. >1 MOhm,
  • Maximum gain for seismic signal: 100000.
  • Limit seismic signal level input: <100 V.
• Synchronization.
  • Input/outputs: TTL
  • Output signal DAC level: 1.2 V cut.
• Analog Filtering.
  • Active Butterworth filters of 4-th order.
  • Slope: 45 dB/oct.
  • high-pass 20, 60,120,230,300 Hz;
  • low-pass 400,800,1000,1500,2800 Hz.
• Digital recording
  • 14bit ADC.
  • Conversion frequency up to 8 kHz
  • Format for seismic recorder: SEG-Y.