TM9100 Service Manual
Frequency Synthesizer Fault Finding
169
© Tait Electronics Limited
August 2005
9
Frequency Synthesizer Fault Finding
Introduction
This section covers the diagnosis of faults in the frequency synthesizer.
The sections are divided into the following:
■
Initial checks
■
Fault diagnosis of RF PLL circuitry
■
Fault diagnosis of FCL circuitry
The initial checks will indicate whether it is the RF PLL or the FCL that is
suspect. Note that the synthesizer is a closed-loop control system. A fault in
one area can cause symptoms to appear elsewhere. Locating the fault can
therefore be difficult.
Measurement
Techniques
The radio must be in CCTM for all the fault-diagnosis procedures of this
section. The CCTM commands required are listed in
Table 9.1
. Full details
of the commands are given in
“Computer-Controlled Test Mode
(CCTM)” on page 112
. Use an oscilloscope with a x10 probe for all voltage
measurements required. The signals should appear stable and clean.
Consider any noise or unidentified oscillations as evidence of a fault
requiring investigation. Use a frequency counter for all measurements of
high frequencies. The RF power output from the frequency synthesizer will
not exceed 10 mW. If a probe is used for frequency measurements, use the
x1 setting.
Table 9.1
CCTM commands required for the diagnosis of faults in the frequency synthesizer
Command
Description
72
101
x
y
0
205
301 0 10
302 0 10
334
x
335
x
389
x
393 1
x
Read lock status of RF PLL, FCL and LO2 — displays
xyz
(0=not in lock, 1=in lock)
Set transmit frequency (
x
in hertz) and receive frequency (
y
in hertz) to specified values
Reset calibration parameters to their default values
Calibrate VCXO of FCL
Calibrate VCO(s) of RF PLL
Set synthesizer on (
x
=1) or off (
x
=0) via DIG SYN EN line
Set transmit-receive switch on (
x
=1) or off (
x
=0) via DIG SYN TR SW line
Set synthesizer mode to slow (
x
=0) or fast (
x
=1)
Write data
x
to FPGA
Summary of Contents for TM9100
Page 1: ...TM9100 mobiles Service Manual MMA 00017 01 Issue 1 August 2005 ...
Page 4: ...4 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 10: ...10 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 22: ...22 Introduction TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 62: ...62 Description TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 96: ...96 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 138: ...138 Disassembly and Reassembly TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 152: ...152 Servicing Procedures TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 168: ...168 Interface Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 244: ...244 Receiver Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 396: ...396 CODEC and Audio Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 420: ...420 Fault Finding of Control Head TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 426: ...426 Spare Parts TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 430: ...430 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 444: ...444 TMAA04 05 Ignition Sense Kit TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 448: ...448 TMAA10 01 Desktop Microphone TM9100 Service Manual Tait Electronics Limited August 2005 ...