Working with Responses to Get Units of Ground Motion
Necessary information:
Sensor: sensitivity and passband (velocity transducer) or scaling (accelerometer)
- For information on sensor sensitivity and passband, see the Sensor Comparison Chart along with the Sensor Response Plot.
Datalogger: Analog-to-Digital (A/D) conversion factor (aka bit weight) and Gain
- Quanterra model Q330: 419,430 counts/volt, or 2.384 uV/count at a Gain of 1
- RefTek model RT130: 629,327 counts/volt, or 1.58997 uV/count at a Gain of 1
Example: Counts to Ground Velocity Conversion within the Passband
The appropriate conversion within the passband would be:
| Amplitude(counts) * A/D conversion factor(V/counts) | ||
| ground velocity (m/s) | = | ---------------------------------- |
| Gain * Sensitivity (V/m/s) |
Suppose your sensor is an STS-2 and your datalogger is an RT130 with its Gain set to 1.
| (1.58997E-06 V/counts) | |||
| ground velocity | = | Amplitude(counts) * | -------------------------------- |
| 1 * (1500 V/m/s) |
For information on SENSOR sensitivity and passband, see the Sensor Comparison Chart along with the Sensor Response Plot.
