HP 8340A Operating Manual page 216

1. Adjust the 8340A to a
then press
2. Turn the 8340A off, press
or change the instrment settings in any
way desired.
3. Press
on the 9826A. Verify on the
analyzer's CRT display and/or the 8340A front
panel that the original instrument state has been
restored.
EXAMPLE PROGRAM
sent Value Of A Function
While the 8340A Learn String enables the user to
save a string of characters that completely defines
the present instrument state, the information is
densely packed and encoded to save memory
space. If the user wishes to determine the actual
value of a specific parameter, say the Start Fre­
quency, it would require a tedious process to
extract a numeric value from several characters
within the Learn String. An eaiser approach is to
use the Output Interrogated Parameter function of
the 8340A. With this function the 9826A instructs
the 8340A to output the present numeric value of
a specified function.
numeric value associated with it can be inter­
rogated even if this function is not presently ac . t ive.
The following program demonstrates the capability
of the interrogate f.unction. It shows how to get the
current value of a parameter whether it has been
entered in the 8340A or computed by the 8340A
internal processor.
PROGRAM
6
!OUTPUTS FROM 8340A
10
20 S0=719
30 PRINT CHR$(12)
OUTPUT S01"1PPM1"
40
50 DISP "ADJUST START FREQUENCY WITH
60 OUTPUT S01"FAEK"
70
PAUSE
80 OUTPUT S01"0A"
90 ENTER SO I A
100 DISP "ADJUST STOP FREQUENCY WITH KNOB"
110 OUTPUT 801 "FBEK"
PAUSE
120
130
DISP
140 OUTPUT S01"0A"
150 ENTER· so,e
160 C=<B-A)/2+A
170 OUTPUT S01"0PCF"
ENTER so,n
180
190 PRINT "CF computed by
200 PRINT "CF output
210 OUTPUT S01 "CW20GZPL15DB"
220 DISP "PRESS CONTINUE TO OUTPUT THE POWER"
PAUSE
230
240
OUTPUT SO 1 "OR"
250 ENTER so,P
DISP
260
270 PRINT "POWER LEVEL
280 PRINT "Real Output POWER LEVEL
END
290
instrument state,
on the 9826A.
Interrogating The Pre­
6:
Any function that has a
KNOB"
9826A is"1C/1.E+61"MHz "
8340A is"1D/1.E+6i"MHz"
fr·om
in ENTRY display is 15 dBm"
is "1P 1 "dBm"
Scans by HB9HCA and HB9FSX
PROGRAM EXPLANATION:
6
lines
10-40: Assign SO to the 8340A address. Then
clear the 9826A CRT, set the 8340A in
the Instrument Preset state and enable
the 8340A pulse modulation for use with
the 2 7.8 kHz square wave modulation
from the
Analyzer.
50-70: Enable the knob to adjust Start Fre­
quency and temporarily halt the pro­
gram.
80-90: Program
numeric value associated with the last
active function. (In this case, START FRE­
QUENCY). This value is then entered in
the variable A.
100-120: Enable the knob to adjust Stop Fre­
quency and temporarily halt the pro­
gram.
130:
Clear the display line on the 9826A
CRT.
140-150: Same as lines 80-90 for Stop Frequency.
160:
The 9826A computes Center Frequency
from the A and B variables and stores
this in the variable C.
170-180: Program the 8340A to output the current
value of a specified parameter. In this
case, the desired parameter is the CF
computed by the internal processor of
the 8340A from the Start and Stop fre­
quencies previously entered. This value
is then stored in the variable D.
190-200:
Display both values of Center Frequency
stored in C and D.
210-230: Program CW frequency to 20 GHz and
power level to 1 5 dBm. Then, output a
prompt to the user and temporarily halt
program execution.
240-250: Program the 8340A to output the real
output power. This is done with the OR
command, which reads the value shown
in the POWER
8340A, which is always the actual power
of the signal coming out of the RF
c o n n e c t o r . T h e v a l u e o b t a i n e d is
assigned to P.
260-290: Display prompts and print the value of
power in the ENTRY DISPLAY on the
8340A and the value of power in the
POWER dBm display on the 8340A.
12
8755C Scalar Network
the 8340A to output
dBm display of
the
the