Stanford Research Systems SR780, Руководство по эксплуатации и программированию

Страница: 457 / 497

Data Transfer Commands 5-91
SR780 Network Signal Analyzer
The host interface must be capable of binary transfer, i.e. accepting line feeds and
carriage returns as data rather than terminators. In addition, the host program
must read exactly the correct number of bytes (4xlength or 8xlength). While a
binary transfer is in progress, the analyzer will not respond to any other queries
and the displays will not update.
If the host program does not start reading the points within 1 second, or pauses
for 1 second while reading, the binary transfer will be aborted.
To read the data in a Trace, recall the Trace to a display and then read the
display.
DSWB ? d, i {, j}
The DSWB? command returns the data in waterfall display d in binary format.
This command is only available with the GPIB interface. The parameter d selects
Display A (0) or Display B (1). This command is not valid if display d does not
have waterfall storage on.
The DSWB ? d, i, j command returns the data value of bin j in record i only. The
bins are numbered from 0 to length-1. The records are numbered from 0 to the
current number of records stored. The value is returned as a 4 byte IEEE float.
The DSWB ? d, i command returns all of the data in record i in binary format.
Do not serial poll for IFC (bit 7) in the Serial Poll status after DSWB? is sent.
IFC will NOT be set until the transfer is complete. Send the command and then
make the host computer a listener and the SR780 a talker.
The DSWB? d, i returns 4 bytes per bin starting with bin 0 and continuing to bin
#(length-1). There is no separation between data points. No line-feed follows the
last data point, instead, EOI is asserted with the last byte. The 4 bytes are an
IEEE floating point number.
The host interface must be capable of binary transfer, i.e. accepting line feeds and
carriage returns as data rather than terminators. In addition, the host program
must read exactly the correct number of bytes (4xlength). While a binary transfer
is in progress, the analyzer will not respond to any other queries and the displays
will not update.
If the host program does not start reading the points within 1 second, or pauses
for 1 second while reading, the binary transfer will be aborted.
DBIN ? d, j
The DBIN? command queries the frequency or time of bin j in display d. The
parameter d selects Display A (0) or Display B (1). The parameter j is bin from 0
to length-1.
The returned value is either a frequency (spectra), a time (time record or
correlation) or a band center frequency (octave).