HP 8340b - Page 82

RS Reset Sweep, causes the HP 8340B/41B to retrace to the start frequency. If a sweep is in pro¬
gress when an RS code is received, the sweep will abruptly terminate and retrace. In BASIC:
100 OUTPUT 719; "RS"
SFdt Step Frequency size, sets the size of the frequency increment that can be stepped by UP or
DN (equivalent to the up/down front-panel [STEP] keys). The SF code is equivalent to the SHCF
code, and both are equivalent to the [SHIFT] [CF] keystroke operation (as described in Figure
3-7).
The SF step size can be as small as 1 Hz, as large as 10 GHz, or it can be coupled to the AF
frequency span with the AU (auto) code (the coupling is explained in Figure 3-7). A BASIC exam¬
ple:
100 OUTPUT 719; "SF 1 MZ"
110 OUTPUT 719; M C W 400 MZ"
120 FOR N = 1 TO 200
130 OUTPUT 719; "UP"
140 NEXT N
ISO GOTO 110
This program sets the step size to 1 MHz, establishes a starting CW frequency of 400 MHz, then
performs a 400-600 MHz discrete sweep.
SG Single sweep, is identical to the S2 code, and both are equivalent to the front-panel [SINGLE] key
which is described in Figure 3-11. SG causes the HP 8340B/41B to perform single sweeps, and is
used in conjunction with the TRIGGER codes (T1, T2, and T3). If trigger code T1 ([FREE RUN]) is in
effect, the SG code (or the TS code) is output every time a single sweep is needed. If SG is output
in the middle of a sweep, the sweep will abruptly terminate and retrace. A BASIC example:
100 OUTPUT 719; "IP SG T1"
110 PRINT "PRESS [CONTINUE] TO START THE SWEEP"
120 PAUSE
130 OUTPUT 719; "SG"
140 GOTO 120
SMdt Sweep Manual, is identical to the S3 code, and both are equivalent to the front-panel
[MANUAL] key which is described in Figure 3-11. SM is used by first establishing the start and
stop sweep frequencies, then outputting SM to activate manual sweep mode. A BASIC example:
100 OUTPUT 719; "IP FA5GZ SF1MZ FB15GZ EK SM"
This example sets a 5 GHz start frequency, a 1 MHz frequency step size, and a 15 GHz stop
frequency. The last two codes in line 100 enable the rotary [KNOB] and activate manual sweep
mode. In addition to [KNOB] control of the sweep, UP and DN can be used and would have a 1
MHz step size.
There are two significant differences between manual sweep and a stepped CW sweep:
1 The sweep voltage ramp (see Figures 3-13 and 3-18, SWEEP OUTPUT) is 0-10 volts for both
modes; however, in CW mode 0 volts always corresponds to 10 MHz and 10 volts always
corresponds to 26.5 GHz (in the case of the HP 8341B, 7.55v at 20.0 GHz), while in manual
sweep mode 0 volts corresponds to the start frequency and 10 volts corresponds to the stop
frequency. In both cases the sweep voltage at intermediate frequencies is a linear interpola¬
tion of the frequency span (i.e., a frequency half-way between the start/stop limits would
have a corresponding sweep voltage of 5 volts).
2. The bandcrossing in CW mode always occur at preciesely 2.4 GHz, 7.0 GHz, 13.5 GHz, and,
in the case of the HP 8340B, 20.0 GHz. In manual sweep mode the bandcrossing points have
200 MHz of flexibility and could, for example, accomplish a 13.45-20.05 GHz sweep in a
single band instead of the three bands required in stepped CW (8340B). The HP 8340B/41B
automatically adjusts the manual sweep bandcrossing point for optimum results.
HP 834QB/41B
Operating Information
3-79