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Low Level Processing Data Products
As it was explained in Section 3.1 JEM-X has five
different telemetry formats: Full Imaging, Restricted Imaging,
Spectral/Timing, Spectral and Timing. The information sent to ground
in Restricted Imaging mode
is enhanced with the count rate of the events. The time resolution of these
Count Rate data is 125 ms, while the rate of the image transfer in this mode
depends on the brightness of the source and may be up to 32 seconds for the
faintest
ones, see Table 2 for an overview.
During data taking JEM-X instruments can switch autonomously between two
preplanned
modes according to the fill status of an on-board buffer, thus avoiding data
loss due to the
buffer overflow, if the secondary mode allows higher transmission rate.
In addition to the mode switching there is also a grey filter mechanism which
can reduce the telemetry load by rejecting a given number (up to and
including 31) out of 32 hardware triggers.
The value of the grey filter setting can vary from G=31 (all events are accepted)
to G=0 (only one event from each 32
is accepted). In general, value G of grey filter means that 31-G events from 32
are rejected.
Table 26 summarizes
all scientific data structures created in these modes.
The data structures for JEM-X 1 and JEM-X 2 have the similar names, so
to avoid the unnecessary repetition we write JMXi, where it should be replaced
by ``1'' or ``2'' depending on the instrument.
Table 26:
List of JEM-X RAW, PRP and COR Data Structures
|
|
|
|
Telemetry Format |
Raw |
Prepared |
Corrected |
|
Data Structure |
Data Structure |
Data Structure |
|
Contains RAW |
Contains |
Contains Corrected |
|
event/spectral data |
event/spectral OBTs |
event/spectral data |
Full Imaging |
JMXi-FULL-RAW |
JMXi-FULL-PRP |
JMXi-FULL-COR |
Restricted Imaging (REST) |
JMXi-REST-RAW |
JMXi-REST-PRP |
JMXi-REST-COR |
Count Rate for REST |
JMXi-RATE-RAW |
JMXi-RATE-PRP |
JMXi-RATE-COR |
Spectral/Timing |
JMXi-SPTI-RAW |
JMXi-SPTI-PRP |
JMXi-SPTI-COR |
Timing |
JMXi-TIME-RAW |
JMXi-TIME-PRP |
JMXi-TIME-COR |
Spectral |
JMXi-SPEC-RAW |
JMXi-SPEC-PRP |
JMXi-SPEC-COR |
Subsections
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