3. Use the following equation to determine the first LO span used.
First LO Span
=
Display Span Setting
Current Band Harmonic Mixing Number
4. Refer to Table 11-13 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 above are affected, perform the
YTO Adjustment procedure in Chapter 2, “Adjustment Procedures.”
a. On the spectrum analyzer press (CAL),
EEALTGN
LO
Ik
IF , and retest all spans.
b. If the YTO adjustment has sufficient range and only LO spans of 2.01 MHz or above are
faulty, test YTO linearity by performing step c.
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 All YTO.
2. If only first LO spans of 2 MHz or less are faulty, suspect the Al4 fractional N PLL.
3. If there are several spans in the main coil and FM coil ranges affected, suspect the Al4
span attenuator.
Synthesizer Section 1
l-37
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