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Leveling Keys/Input
DESCRIPTION
Internal or external (crystal or power meter) power leveling is selected by these keys which also
select a band crossing diagnostic and allow direct linear modulator access. The external leveling B
input connector is also described in this Figure.
PANEL LAYOUT
EXT INPUT
INT
XTAL
METER
- LEVEL ING-
FUNCTIONS
EXT INPUT BNC connector is the input port for an external leveling signal. The signal requirements
are listed in the specification tables in Section I. See the Operating Guide "Externally Leveling the
8340B/41B Synthesized Sweeper," located at the end of Section III, for detailed information about
external leveling procedures.
TINT] (HP-IB:
A1) selects internal leveling of the HP 8340B/41B. The specifications tables in Section I
list the maximum leveled power for each frequency band, and other power function restraints.
FSHIFT1 riNTl (HP-IB-
SHA1) bypasses the ALC (automatic leveling control) and allows the user to
select a power level to be set in the unleveled mode. The benefit of this function is that an unleveled
output power level can be set via HP-IB while allowing; the synthesized sweeper to be pulse modu¬
lated with no limit to the minimum pulse reptition frequency and ^
bandwidth while simultaneously pulse modulating. Press [SHIFT] [INT],
POWER SEARCH XXX
dBm" will appear in the entry display. The previous internally leveled power will be set automatically.
To enter a different power use [KNOB], [STEP] keys or numeric keypad terminate with the [dBm] key.
rXTALl (HP-IB:
A2) activates external crystal leveling of the HP 8340B/41B. A portion of the RF
output (derived from a coupler or a splitter) must be detected, with the detected output being delivered
to the EXT INPUT BNC connector, thus forming an output-input feedback loop (the loop typically has
80 kHz bandwith). Press [XTAL], and "ATN: -xx dB, REF:
-xx.xx dBV" (where x is the last-
entered value) will appear in the entry display. Then use the rotary [KNOB] or the numerical keys with
the [dB(m)] terminator key to change the REFerence level, and the [STEP] keys to change the ATN
while watching either the POWER dBm display (allowing for losses in the coupler or splitter) or an
attached power meter. The "Externally Leveling the HP 8340B/41B Synthesized Sweeper operating
guide located at the end of this section fully explains crystal leveling and shows typical equipment
interconnections.
rSHIFT] [XTAL] (HP-IB:
SHA2) activates the external source module leveling mode. A portion of the
mm-wave signal from the HP 83550 series mm-wave Source Module is detected ^delivered to th®
EXT INPUT BNC connector, thus forming an output-input feedback loop. Press [SHIFT] [Xialj ana
"EXT MODULE POWER: xx.xx dBm" will appear in the entry display. Enter the desired externally
leveled module power using either the [KNOB], [STEP] keys, or numeric keypad. Terminate with the
[dBm] key.
Figure 3-16.
Leveling Keys/Input (1 of 2)
HP 8340B/41B
Operating Information
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