Using Scream!
rate to 4 (Hz). In this manner, you can select frequencies ranging from 0.1 to 10 Hz (10
to 0.1 s periods).
You can specify step calibration by selecting the
Square wave
button. The square
wave consists of a positive step at the start of the next minute of the digitiser’s
internal clock, followed by a negative step after a specified number of minutes. After
a further delay of the same number of minutes, the calibration signal is
disconnected. The default is 2 minutes. The
Period
and
Frequency
settings are
ignored.
The
Broadband Noise
calibration signal consists of a constant stream of white noise,
which lasts for the specified number of minutes. The
Period
and
Frequency
settings
are ignored.
5.2.4 Mass Control
Many Güralp instruments respond to control signals to centre, unlock, and lock the
sensor masses. These signals are generated by the digitiser. You can tell the
digitiser to send a signal using the
,
and
buttons on the
Mass Control
tab.
If you select
Monitor progress
, the window will remain open during the process, and
the mass positions will be displayed in the
Vertical
,
N/South
and
E/West
boxes. If
you leave
Monitor progress
unselected, the window will close. You can still monitor
mass positions by selecting the appropriate streams and opening a WaveView
window for them.
Depending on which Sensor Type you have chosen in the System tab (see above), not
all the control signals will be available. For example, a Güralp 3ESP can be centred
53
Issue U - December, 2021
