Guralp Systems CMG-3ESPCD - Manual (Page 83)

CMG-3ESPCD Digital Broadband Seismometer Inside the 3ESPCD
This arrangement results in two poles at specified frequencies. The velocity
response of a conventional-response system is defined by a transfer function
identical to that of a conventional long-period sensor with a damping constant
of 0.707 (1/√2). ζ
The seismometer can be supplied with an equivalent resonant frequency of
0.033 Hz (30 s), 0.01 Hz (100 s) or 0.0083 Hz (120 s) as required. An active
low-pass filter provides a high-frequency cut-off point at a frequency you
specify.
MAN-C3E-0002 83 Issue B - November 2013