Guralp Systems CMG-3TB - Manual (Page 62)

CMG-3TB
The bbnoisecal script automatically performs appropriate
averaging to reduce the effects of aliasing and cultural noise.
Sensor response codes
Sensor Sensor type code
Units
(V/A)
CMG-3TB, 30 s – 50 Hz response CMG-3B_30S_50HZ V
CMG-3TB, 100 s – 50 Hz response CMG-3B_100S_50HZ V
CMG-3TB, 120 s – 50 Hz response CMG-3B_120S_50HZ V
CMG-3TB, 360 s – 50 Hz response CMG-3B_360S_50HZ V
CMG-3TB, 360 s – 100 Hz response CMG-3B_360S_100HZ V
4.4 Calibration with a handheld control unit
If you prefer, you can inject your own calibration signals into the
system through a handheld control unit. The unit includes a switch
which activates the calibration relay in the seismometer, and 4 mm
banana sockets for an external signal source. As above, the equivalent
input velocity for a sinusoidal calibration signal is given by
v = V / 2 π f R K
where V is the peak-to-peak voltage of the calibration signal, f is the
signal frequency, R is the magnitude of the calibration resistor and K is
the feedback coil constant. R and K are both given on the calibration
sheet supplied with the 3TB.
The calibration resistor is placed in series with the transducer.
62 Issue C