556 Chapter10
Synthesizer Section
Frequency Span Accuracy Problems
3. Use the following equation to determine the first LO span used.
4. Refer to Table 10-15 on page 555 to determine the circuit associated
with the span.
Confirming Span Problems
1. If all first LO spans or only first LO spans of 2.01 MHz or greater are
affected, perform the YTO Adjustment procedure in Chapter 2.
• On the HP 8560E/EC press
CAL, REALIGN LO &IF, and retest all
spans.
• If the YTO adjustment has sufficient range and only LO spans of
2.01 MHz or greater are faulty, test YTO linearity by performing
step c.
• Test the span in question at different center frequencies in the
same band. If the span accuracy changes significantly (2% or
more), suspect the A11 YTO.
2. If first LO spans of 2 MHz or less only are faulty, suspect the A14
fractional N PLL.
3. If there are several spans in the main coil and FM coil ranges
affected, suspect the A14 span attenuator.
YTO Main Coil Span Problems (LO spans >20 MHz)
For YTO main coil spans, the YTO is locked at the beginning of the
sweep and the sweep ramp is summed into the main coil tune driver.
1. Perform the YTO adjustment procedure in Chapter 2. If the YTO
adjustments cannot be performed, continue with step 2.
2. Set the HP 8560E/EC to the following settings:
Start frequency .......................................................... 10MHz
Stop frequency ........................................................... 2.9GHz
Table 10-16 Harmonic Mixing Number versus Center Frequency
Center Frequency Harmonic Mixing Number
1 kHz to 2.9 GHz 1
18 GHz to 325 GHz 6 through 54 depending upon
lock harmonic selected
First LO Span
Display Span Setting
Current Band Harmonic Mixing Number
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