User Guide

CC Technical Documentation Troubleshooting - RF (Part 2)

RM-11

UHF Synthesizer Layout

Figure 7: UHF synthesizer layout

UHF Frequency is Incorrect

Possible causes:

• Power supplies to PLL IC (N507) are missing or low

• Loop filter components missing or incorrectly installed

• 19.2MHz reference clock missing or low

• Programming is incorrect

• Component failure (VCO or PLL IC)

RX VHF (Batman LO) Schematic

• Operates at a fixed frequency of 256.2MHz. It is the second LO for

down-conversion to I and Q for baseband processing. Refer to the frequency

plan.

• Monitor probing point at C702 for Batman LO. A locked and stable 256.2MHz

with an amplitude of ~= -2.5dBm should be observed on the spectrum analyzer.

• Monitor control voltage at C715. The control voltage at locked state should be

between 1.2 and 1.7VDV for the proper operation of Batman LO.

UHF PLL IC LMX2310

VCTCXO reference probing point

19.2 MHz @ +4.5 dBm

Lock voltage:

DC between 1V and 3V

RX LO Input to Alfred

Cell channel 384: 1009.62 MHz @ -2.5 dBm

PCS channel 600: 2088.10 MHz @ -12 dBm

Dual-band UHF VCO

TX LO Buffer

RF probe point, TX LO output levels:

Cell channel 384: 1009.62 MHz @ -0.5 dBm

PCS channel 600: 2088.10 MHz @ -20 dBm