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Model 5344S
Operation and Programming
3-77.
In Subharmonic Locking Mode, the AUX OUT (YIG fundamental) is applied to the
counter input. Then the rear panel SUB HMNC/NORM switch is placed in the SUB HMNC
position. This performs two functions: (1) enables the use of a Frequency Multiplier number, and
(2) extends the 5344A's upper and lower numeric input limits. Frequencies not equal to the front
RF OUT (but harmonically related) and frequencies above 18 GHz (5342A) or 26.5 GHz (5343A)
can be entered. The 5344S compares the entered frequency on the 5344A to the frequency being
applied to the counter, and determines the Frequency Multiplier number required, provided
this number is within the range of 1 to 4. If the Frequency Multiplier number required is greater
than 4, it must be entered manually. The highest allowable value is 99. See Frequency Multiplier,
paragraph 3-89.
3-78.
For example, the YIG is tuned to 5.0 GHz (at AUX OUT), but 20 GHz has been selected on
the 5344A front panel. The 5344A determines the Frequency Multiplier number to be 4. The 5.0
GHz signal being applied to the 5342A is well within the 18 GHz limit.
3-79.
However, if the selected value on the 5344A is 25 GHz, the 5344A will display Err 09, since
the multiplier is 5, and the 5344A cannot automatically determine this. The multiplier of 5 must be
manually entered. See Frequency Multiplier, paragraph 3-89.
3-80.
Detailed Frequency Offset Locking
3-81.
Frequency Offset Locking allows the 5344S to operate with sweeper plug-ins that can
generate signals below the 5344S's lower limit of 500 MHz. In this mode, the 5344S can control
plug-ins down to 10 MHz. In the following example, the range of the plug-in is 10 MHz to 2.4
GHz. This range is generated using the YTO and Fixed Frequency Oscillator (Cavity Oscillator)
described in paragraph 3-64.
3-82.
Instead of applying the front panel RF output of the plug-in to the 5344S's counter input,
the rear panel AUX OU T (YTO) is used. The AUX OUT is always 3.8 GHz higher (offset) than the
front panel RF OUT. The YTO range is from 3.81 to 6.2 GHz. As can be seen, this range is above the
counter's 500 MHz lower limit. Since the offset is constant, the 3.8 GHz can be subtracted from
the counter's display.The display will now always be equal to the plug-in's front panel RF OUT.
3-83.
The 5344S controls the plug-in over the range of 3.81 to 6.2 GHz. The YTO is being mixed
with the Cavity Oscillator to generate a lower frequency. The Cavity Oscillator frequency (3.8
GHz) being subtracted from the counter's display is for user convenience only. This ensures the
5344S display and the counter's display are consistent.
3-84.
The offset is not subtracted from the counter's display under the following conditions:
1.
Manual or Auto Lock is off.
2.
Manual or Auto Lock is on but the 5344S is out of lock.
3-85.
Under these conditions, the counter will display the actual rear panel AUX OUT (YTO)
frequency.
3-86.
The rear panel MODE switch must be in the SUB HMNC position.
3-87.
Since the Cavity Oscillator is not being controlled, any variation in the Cavity Oscillator's
frequency is directly reflected in the plug-in's front panel RF OUT.
3-10
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