HP 8920B, Руководство программиста

Страница: 257 / 682

257
Chapter 5, Advanced Operations
Increasing Measurement Throughput
Example #3
OUTPUT 714;"ENC:AMPS:SAT:FM 2.35 KHZ;FREQ 5.970 KHZ"
!This OUTPUT statement sets the AMPS SAT tone’s frequency and deviation.
The semicolon separator tells the Test Set’s HP-IB command parser to back up only
one
level of command hierarchy. The following OUTPUT statement illustrates
improper
use
of the semicolon separator.
OUTPUT 714;"RFG:MOD:EXT:DEST ’FM (/Vpk)’;AOUT ’DC’"
Trying to execute this OUTPUT statement would cause
HP-IB Error:-113
Undefined header
. This is because the AOUT command is two levels higher
than the DEST ’FM (/Vpk)’ command. Refer to the
RF Generator syntax diagram,
on page 179
for the command hierarchy.
The ;: (semicolon-colon) Separator.
The ;: (semicolon-colon) separator tells the
Test Set’s HP-IB command parser that the next command is at the top level of the
command hierarchy. This allows commands from different instruments to be
output on one command line. The following example illustrates proper use of the
semicolon-colon separator:
Example
OUTPUT 714;"RFAN:FREQ 850 MHZ;:AFAN:INP ’FM DEMOD’"
This OUTPUT statement sets the RF Analyzer’s tune frequency to 850 MHz, and then sets
the AF Analyzer’s input to FM Demod.
Compound Commands for Combining ENTER Statements
To reduce the number of ENTER statements used to read measured values within
one screen, string together multiple measure commands within one OUTPUT
statement followed by an ENTER statement with the appropriate number of
variables to hold the measured values. The following example illustrates this
technique.
Example
OUTPUT 714;"MEAS:RFR:POW?;FREQ:ABS?"
ENTER 714;Power,Freq_abs
This OUTPUT statement requests an RF power and an absolute RF frequency
measurement. The ENTER statement then reads both values into program vari-
ables.