Guralp Systems CD1.1 - Manual (Page 12)

CD1.1 Tools for Platinum
The subframes contain a number of additional data beside the
samples:
•
Channel meta-data is used to populate the “instrument
type” and “gain” fields
•
The “channel status” field is populated using
information from the state-of-health data provided by
gdi-base, from the anti-tamper lines (and other digital
input/output fields) and from the internal temperature
and voltage monitoring subsystems.
•
Optionally, a cryptographic signature generated by a
hardware engine (such as the Spyrus encryption card).
Operation of such hardware is discussed in chapter 10
on page 67.
The subframes can support any sample rate and can be of
various durations (in multiples of 10 seconds).
2.2.1 Channel Subframe Status Field
The gdi2cd11 module implements the first permitted status
field as defined with format value = 1 in the CTBTO standard
revision 0.2. There are several reserved bits and bytes in the
standard, and these can optionally be mapped to additional
details in the gdi2cd11 configuration (see section 6.2.1 on page
34).
The meaning of the bits is mapped as follows (counting from 1,
with 1 being the least significant bit and 8 the most):
12 Issue C