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[PWR SWEEP] (HP-IB:
PS1 turns on power sweep, PSO turns off the function) allows the power
output to be swept when the HP 8340B/41B is in CW mode. This is the procedure:
1.
Select a CW frequency, as explained in Figure 3-7.
2.
Press [SHIFT] [PWR SWEEP], which decouples the attentuator (ATN) from the automatic leveling
control (ALC) and displays the ATN and ALC values in the ENTRY DISPLAY. The ALC range is
—20 dBm to an upper value that depends on frequency (see the specifications given in Section I).
3.
Use the [STEP] keys to set the value of the ATN, and the [KNOB] or numerical keys with [dB(m)]
terminator key to set the ALC for the starting power level, as shown in the POWER dBm display.
The ALC value should be as close as possible to -20 dBm to achieve the widest-span power
sweep.
4. Set the [SWEEP TIME], as explained in Figure 3-7.
5.
Press [PWR SWEEP] and "POWER SWEEP: x.xx db/SWP'' (where x is the last-entered value)
will appear in the ENTRY DISPLAY. Use either the [KNOB], the [STEP] keys, or the numerical
keys with the [dB(m)] terminator key to select the span of the power sweep (positive values only,
ranging from 0.0 to 40.00 dB/SWP).
6. Select SWEEP and TRIGGER, as described in Figure 3-11.
If only narrow-span power sweeps are necessary, the ATN does not need to be decoupled from the
ALC: Omit steps 2 and 3 in the preceding text using instead the [POWER LEVEL] key to set the initial
power output. This simplified procedure restricts the range of power sweeps to that of the coupled
ALC, which is —9.95 dBm to the maximum power permitted (maximum power depends on frequency,
as listed in the Specification Tables.
[SHIFT] [PWR SWEEP] (HP-IB:
SHPS) decouples the attenuator (ATN) from the automatic leveling
control (ALC), as explained in the preceding function. Recouple the ATN and ALC by pressing
[POWER LEVEL],
[SLOPE] (HP-IB:
SL1 turns on the slope function, SL0 turns off the function) compensates for sys¬
tem or cable losses at high frequencies by linearly increasing the power output as the frequency
increases. Press [SLOPE] and "RF SLOPE: xx.xx dB/GHz" (where x is the last-entered value) will
appear in the ENTRY DISPLAY. Use either the [KNOB], the [STEP] keys, or the numerical keys with
the [dB(m)] terminator keys to set any positive slope value between 0.000 to 1.500 dB/GHz. Press
[SLOPE] again to cancel this function. [SLOPE] functions in dB/GHz units, but SL (the equivalent HP-
IB code) functions in the fundamental units of dB/Hz. Therefore, the SL code should be programmed
as SLmdt, where m is 0 (off) or 1 (on), d is the numerical value in dB/Hz, and t is either "DB" or the
ASCII LF terminator. For example, to obtain a slope of 1.5 dB/GHz use this procedure:
1.
1.5 dB/GHz = 1.5 dB/1,000,000,000 Hz
2. 1.5 dB/1E9 Hz = 1.5E-9 dB/Hz
3.
Programming code is then "SL11.5E—9 DB".
[SHIFT] [SLOPE] (HP-IB:
SHSL) allows front panel control of the mechanical attenuator (ATN).
Press [SHIFT] [SLOPE] and "ATN:
x dB" (where x is the last-entered value) will appear in the
ENTRY DISPLAY. Use the [STEP] keys, or the numerical keys with any terminator key to change the
attenuator value within the range 0 dB to—90 dB in 10 dB steps. Keyboard entries are automatically
rounded to the nearest 10 dB. The clicking sound heard after each attenuator change is the attenuator
pad being mechanically switched into the RF output path.
Figure 3-17.
RF Keys/Output (2 of 3)
3-40
Operating Information
HP 8340B/41B
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