|
Mode
|
Date
|
Rate
|
Description
|
| RF-thresh.INTF |
August 23, 1995 -
present
|
500 kHz
(+5 kHz continuous SA)
|
15 channels (12 8-bit I/Q phase, 2 12-bit FA/SA, 1 8-bit log-RF) of
data is acquired continuously from the A/D boards at 500 kHz rate.
The DSP performs a tangent lookup real-time in order to convert the 8-bit
I/Q pairs to single 8-bit phase values (this nearly halves the raw data
rate). Every time the log-RF is above a user-specified threshold
for a user-specified number of times within a 100 microsecond data block,
the data block is stored (provided that an interference condition is not
in effect). The user can also specify that the FA be used as a trigger
source with a configurable post-trigger length. The SA data is not
stored at 500 kHz rate, but is instead forked-off into a separate file
and stored continuously at a 5 kHz sample rate. |
| fa2 (1c2) |
July 11, 1996 -
September 29, 1997
|
500 kHz
|
12-bit FA data is acquired continuously into a circular memory buffer
cell at 500 kHz rate. Whenever the data surpasses a configurable
bipolar (+/-) threshold, the data is stored for the remaining number of
user-specified blocks needed to reach the total trigger length. Both
the pre- and post- trigger lengths are configurable on program startup.
There is no dead time after completing a trigger, so the system can immediately
retrigger (while storing data into another circular memory buffer cell). |
| FA-trig. INTF |
October 6, 1996 -
June 19, 2000
|
500 kHz
|
Like the RF-thresholded interferometer code, this code acquires 15
channels (12 8-bit I/Q phase, 2 12-bit FA/SA, 1 8-bit log-RF) of data continuously
from the A/D boards at 500 kHz rate. Similarly, the DSP performs
a tangent lookup real-time in order to convert the 8-bit I/Q pairs to single
8-bit phase values (this nearly halves the raw data rate). The SA
data is forked-off at 10 kHz rate, but unlike the RF-thresholded code,
it can not be stored continuously. Instead, the SA data is only stored
for the duration of the trigger window. Whenever a configurable bipolar
(+/-) threshold is exceeded on the FA, the data is stored for the remaining
number of user-specified blocks needed to reach the total trigger length.
The pre- and post-trigger lengths can be changed real time. The system
can also be triggered manually (with all pre-trigger and no post-trigger),
even while automatic triggering is enabled. This mode does not work on the
Sun Ultra 1 for unknown reasons. |
| fa1 (1c1) |
October 11, 1996 -
September 29, 1997
|
1 MHz
|
This mode is essentially identical to the fa2 mode. The only
difference is that data is sampled at 1 MHz rate. |
| 3c1 |
July 11, 1997 -
September 29, 1997
|
1 MHz
|
3 channels of data (2 12-bit and 1 8-bit) are acquired continuously
into a circular memory buffer cell at 1 MHz rate. Whenever the 12-bit
"channel 4" (usually FA) exceeds a configurable bipolar threshold, the
data is stored for the remaining number of user-specified blocks needed
to reach the total trigger length. Both the pre- and post- trigger
lengths are configurable on program startup. There is no dead time
after completing a trigger, so the system can immediately retrigger (while
storing data into another circular memory buffer cell).
It should be noted that although the 1-channel sferic acquisition modes
are listed as having been "retired" on September 29, 1997, they were effectively
terminated when 3 channel acquistion was enabled due to the superiority
of this mode. |
| 3c2 |
July 14, 1997 -
September 29, 1997
|
500 kHz
|
This mode is essentially identical to the 3c1 mode. The only
difference is that data is sampled at 500 kHz rate. |
| 7c2 |
September 8-29, 1997
|
500 kHz
|
7 channels of data (2 12-bit and 5 8-bit) are acquired continuously
into a circular memory buffer cell (at 500 kHz rate). Whenever
the 12-bit "channel 4" (usually FA) exceeds a configurable bipolar threshold,
the data is stored for the remaining number of user-specified blocks needed
to reach the total trigger length. Both the pre- and post- trigger
lengths are configurable on program startup. There is no dead time
after completing a trigger, so the system can immediately retrigger (while
storing data into another circular memory buffer cell). |
| 3c2-100 |
September 29, 1997 -
present
|
500 kHz
(+10 kHz continuous)
|
This mode replaced the "3c2" mode. It uses essentially the same
code on the 1st DSP, but adds the 2nd DSP (with DSP intercommunication
code on the 1st) which allows 10 kHz data of all 3 channels to be placed
continuously into the 2nd DSPs circular memory buffer and stored continuously
to disk.
The required host program modifications effectively disabled all other
sferic modes developed previously (most were obsolete anyways). |
| 3c1-100 |
September 2, 1999 -
present
|
1 MHz
(+10 kHz continuous)
|
This mode is essentially identical to the 3c2-100 mode. The only
difference is that data is sampled at 1 MHz rate. |