Guralp Systems CD1.1 - Manual (Page 8)

CD1.1 Tools for Platinum
2 The CD1.1 modules
This section of the manual will describe the function of each of
the four CD1.1 modules in detail. For precise configuration
instructions, please refer to sections 4 through 7.
2.1 The CD1.1 multiplexor (data-mux-cd11)
This is the central store-and-forward module for CD1.1
subframes. Every CD1.1 configuration requires at least one
CD1.1 multiplexor instance to be active. An instance of this
module must be configured before the configuration system
will allow any other CD1.1 modules to be instantiated.
CD1.1 subframes originating from either external CD1.1
sources (via data-in-cd11) or from non-CD1.1 sources (via
gdi2cd11) are transmitted to this module. The multiplexor
stores these subframes, either on disk or in flash RAM, and will
coalesces frames from multiple sources where this is
appropriate. It then forwards complete data frames onwards to
the output stage, data-out-cd11.
Subframes are stored briefly before they are assembled into
frames. There is a trade-off between the data latency - the
amount of time between a subframe's reception and its
transmission as part of a frame - and the overall framing
efficiency - the number of subframes that can be packed into a
single frame. A parametrised algorithm is used to allow the
operator to tune this to suit each application's specific
requirements - see section 2.1.1 on page 9 for more details.
8 Issue C