Table of Contents
Advertisement
There are two significant differences between [MANUAL] sweep and the sweep that can be obtained
by having the
[KNOB]
control an active CW function:
1.
The sweep output voltage ramp (see Figures 3-13 or 3-18, SWEEP OUTPUT) is 0-10 volts in both
modes, but in CW mode 0 volts always corresponds to 10 MHz and 10 volts always corresponds to
26.5 GHz (7.55V at 20 GHz with HP 8341B), 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 interpolation of the frequency span (i.e., a fre¬
quency half-way between the start/stop limits has a corresponding sweep voltage of 5 volts).
2
The bandcrossing points in CW mode always occur at precisely 2.3, 7.0,13.5, and, in the case of
the HP 8340B, 20.0 GHz. In manual sweep mode the bandcrossing points have 200 MHz of
flexibility, which is automatically used by the HP 8340B/41B for optimum performance (for exam¬
ple, a 2.35 to 7.05 sweep could be accomplished without any band changes in manual sweep
mode).
[SHIFT] [MANUAL] (HP-IB:
SHS3) activates the FAULT diagnostic routine. When the amber FAULT
annunciator appears in the ENTRY DISPLAY, press [SHIFT] [MANUAL] to initiate the FAULT diag¬
nostic which will cause "FAULT: CAL KICK ADC PEAK TRK'' to appear in the ENTRY DISPLAY. The
flashing cursor indicates which circuit (CALibration constants, KICK pulses, Analog to Digital
Converter, power PEAKing, or TRacKing) is causing the problem. Refer to the In Case of Difficulty
section.
[FREE RUN]
(HP-IB:
T1) allows internal triggering of the any sweep function, and is the fastest
possible way to accomplish the sweep-retrace cycle.
[SHIFT] [FREE RUN]
(HP-IB:
SHT1) activates the display self-test diagnostic function. Press
[SHIFT] [FREE RUN],
which will cause every segment of every LED in the displays to light, followed by
a marching pattern of every character in the display lexicon. Press
[INSTR PRESET]
or cycle the
POWER switch to cancel this diagnostic routine.
[INSTR PRESET]
will restore the instrument to its
standard starting condition. Cycling the POWER switch will restore the displays to their previous
condition. If this marching display ever appears spontaneously, especially at power-on, the main
processor circuit has failed and Section VIII (Service) should be consulted for further instructions.
Figure 3-11.
Sweep and Trigger Keys (2 of 3)
HP 8340B/41B
Operating Information
3-29
Advertisement
Table of Contents
