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DUm
Display Updating, blanks (DUO) or unblanks (DU1) the front panel displays of the HP 8340B/41B,
and is identical in function to SHSIm ([SHIFT] [CONT], which is described in Figure 3-11). In
automated systems the displays of the HP 8340B/41B might be redundant, and can be blanked to
reduce visual distractions for the operation. A BASIC example:
100
OUTPUT 719; "DUO"
If DU1 is output while the HP 8340B/41B is in the middle of a sweep, the sweep will abruptly stop,
retrace, and the resume sweep operations.
EK
Enable Knob, activates the rotary
[KNOB]
on an otherwise remote HP 8340B/41B front panel.
Once the
[KNOB]
is enabled it is automatically coupled to the presently active function, such as:
100
OUTPUT 719; "CWEK"
([KNOB]
adjusts CW frequency)
200
OUTPUT 719; "PLEK"
([KNOB]
adjusts Power Level)
In the above examples, the CW and PL function
codes were output along with EK to explicitly specify
the active function; since no data accompanied the
function codes, the last-used data values (or the IP
default values) will be re-established. EK can also be
output alone:
300
OUTPUT 719; ,,EKM
310
OUTPUT 719; "CF70MZ"
320
PAUSE
330
OUTPUT 719; "DF1MZ"
340
PAUSE
350
OUTPUT 719; "ST50MS
PL -2SDB"
360
PAUSE
EK always controls the active function; hence, at line 320 the
[KNOB]
controls the center fre¬
quency (initially at 1 MHz); and at line 340 the
[KNOB]
controls the delta frequency (initially at 1
MHz); and at line 360 the
[KNOB]
controls the power level (initially at -25 dBm). Notice at line 360
that the
[KNOB]
controls PL, not ST, because PL is the last-activated function.
FP
Fast Phaselock, is used when the fastest possible frequency transition is necessary between CW
frequencies. FP can be used for fast transitions between steps in a stepped CW sweep, or it can
be used when the CW frequencies must be rapidly changed to any value in the frequency span of
the HP 8340B/41B.
FP achieves rapid frequency transition by limiting some of the normal HP 8340B/41B fea¬
tures: The plotter control functions are disabled, the 0-10 volt sweep ramp is frozen, and the HP
8340B/41B does not wait for a complete locking of the phase lock loop oscillators before releas¬
ing the HP-IB handshake. The FP code must have a numerical suffix (14 characters maximum) in
Hz units, without any terminator code (ASCII "LF," normally sent by the computer is the only
allowable terminator), that sets the starting frequency. A BASIC example of a stepped CW sweep:
100
OUTPUT 719; "IP
SF1KZ
CW"
110
OUTPUT 719; "FP1E9"
120
FOR J = 1 TO 100
130
TRIGGER 719
140
NEXTJ
150
GOTO 110
Line 100 sets the step size (SF) to 1 kHz, and causes the HP 8340B/41B to enter CW mode (the
unspecified CW frequency at this point will be the last used CW frequency, or the IP default value).
Line 110 initiates fast phaselock mode, and establishes a starting CW frequency of 1E9 Hz (1 X109
Hz, or 1 GHz). At this point in the program, the HP 8340B/41B is outputting 1 GHz CW but will not
increment until line 130 is reached. Line 150 causes a retrace to 1 GHz.
HP 8340B/41B
Operating Information
3-65
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