Asus P552W Manual page 97

Otherwise, replace GPS chip (U2001) under the condition of
R2022 at high voltage level but still failure in download firmware.
The last GPS debug process is GPS RF performance test. The
purpose of this debug process is to find out where the problem is on
GPS RF path. In other words, engineers can judge the defect
component on RF path by using "SiRFDemo", one of GPS debug
tools. SiRFDemo enforces GM2 into GPS test mode so that GM2 can
keep receiving GPS signals generated by GPS simulator.
The detail steps of GPS RF performance test and debug are listed
as follows.
a. Set a GPS simulator to emit GPS signal into GM2 GPS RF
connector (CON2002) via a RF cable and a RF adapter (MS-162).
The corresponding satellite number and power are listed in the
following table.
b. Execute SiRFDemo debug tool and related parameters of this
debug tool are prescribed in the appendix. Measure C/N value by
using SiRFDemo and pass criteria is listed in the above table. The
following debug processes are necessary if C/N measurement fail
the criteria.
c. Spectrum analyzer connects with a high impedance probe and
set frequency as it in the above table.
d. Use the high impedance probe to sequentially measure RF
power of test points on GPS RF path, including C2010, L2003,
R2005, and R2027. Corresponding locations of test points are
shown in "i. GPS path and test points." Measurement error of RF
power on each test point is unavoidable due to measurement skills
and operating methods of using high impedance probe. Moreover,
measured RF signal strength of each point must refer to a golden
sample under the same measurement conditions. The results of
measured RF signals on each test point are showed in the
following descriptions.
華 碩 電 腦
華 碩 電 腦
GTC ■ Service Manual
97