Guralp Systems CMG-DCM build <10,000 - Manual (Page 81)

Operator's Guide
•
“Recommended (8-bit 20 records max)” - this setting
represents the best compromise for throughput: allowing 8-
bit compression potentially increases the number of samples
per packet and limiting packets to twenty records guarantees
reasonably low latency.
•
“On (8-bit 250 records max)” - this setting optimises line
utilisation, allowing maximum compression and minimising
the number of packet headers transmitted.
•
“Off (32-bit 20 samples max)” - this setting disables
compression, forcing samples to be transmitted as 32-bit
differences. Latency is reduced by limiting the number of
records to twenty per packet.
If the system is connected to a digitiser that is using a different
combination of compression control and sample limits, it will appear
as an extra item in the drop-down menu, labelled “Custom”. For
example:
•
“Custom (16-bit 40 samples max)”
would appear if these settings had been manually configured from,
say, the digitiser's command line.
The “Decimator outputs” section of the screen shows and controls
which digitiser taps have been configured to output data, both in
continuous and triggered states.
The output column is extended when using 7-channel digitisers. Extra
taps can be added with the “Add new output” button. The rates
available at each tap are dependant on the rate selected at the previous
tap: the base sampling rate is 2000 samples per second and each tap
can be configured to divide this by either 2, 4 or 5. The available rates
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