Giga-tronics 8003, Руководство по эксплуатации

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8003 Precision Scalar Analyzer
3-40 Manual 20791, Rev. C, June 2001
Modifiers: Modifiers Used Only With T2 Mode
Modifier Description: ITEMS activates buffered readings in T2 mode. A Buffer
is memory internal to the analyzer set aside to store
readings. The memory is user defined to any length
between 1 and 512 readings. In buffered reading mode,
the analyzer directs readings to the buffer memory until
the buffer is full. When talk-addressed, the analyzer then
sends the entire buffer full of readings to the controller.
Buffering the data allows the analyzer to measure even
faster since it does not have to output the data to the
controller between each reading. Once a buffer is
specified for one channel, all active channels must use a
buffer of the same size. The last ITEMS n command
received determines the buffer size for all channels.
When n=1 or when ITEMS is not specified, the triggered
mode waits to be talk-addressed after each reading. For
buffer sizes greater than 1, the analyzer does not wait to
be talk-addressed after each trigger, but instead adds
the new reading to each active channel’s buffer. When
the buffer is full, the analyzer halts and waits to be talk-
addressed. When talk-addressed, the analyzer sends
the buffered readings to the controller. The entire buffer
for the lowest channel number is sent first, followed by
the buffer for the next highest channel number, and so
on, until all buffers are sent. Each individual data item is
separated from the next by a comma, and data from the
end of one buffer and the beginning of the next is simply
separated by a comma.
Modifier name: ITEMS
Modifier syntax: ITEMS hs numerical value
Valid numerical values: Any integer between 1 and 512
Modifier Description: SRQ sets up a GPIB handshake for buffered readings in
T2 mode. In GPIB-triggered mode, the analyzer ignores
extra triggers that may occur while the analyzer is
occupied with a reading. When data buffers are used,
this may lead to a situation where the controller thinks
that the 8003 should be through taking data, while the
8003 is waiting for more triggers. One way around this
problem is to ensure that the trigger rate is below the
8003’s maximum data rate. Another way is to use the
optional SRQ modifier to provide a full GPIB handshake.
When the SRQ modifier is added to the
POWER
command, the analyzer will assert the bus SRQ line
after it completes each reading. The controller software
must then be written to wait for the SRQ interrupt before
giving another trigger. Due to the overhead of process-
ing the SRQ interrupt, full handshake operation may be
slower than single-ended triggering of the readings.
Modifier name: SRQ
Modifier syntax: SRQ