Specifications

WM_PRJ_Q2400_PTS_001 - 003
6th November 2002
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5 Design Guidelines
The following paragraphs aims give design guidelines.
5.1 HARDWARE and RF
5.1.1 EMC recommendations
The EMC tests have to be performed as soon as possible on the application to
detect any possible problem.
When designing, special attention should be paid to:
•
Possible spurious emission radiated by the application to the RF receiver
in the receiver band
•
ESD protection on SIM (if accessible from outside), serial link,…
•
EMC protection on audio input/output (filters against 900MHz
emissions)
•
Bias of the Microphone inputs
•
Length of the SIM interface lines (preferably <10cm)
•
Ground plane: WAVECOM recommends to have a common ground plane
for analog / digital / RF grounds.
•
Metallic case or plastic casing with conductive paint are recommended
Note
:
The module does not include any protection against overvoltage.
5.1.2 Power Supply
The power supply is one of the key issues in the design of a GSM terminal.
A weak power supply design could affect in particular:
•
EMC performances
•
the emissions spectrum
•
the phase error and frequency error
Warning:
Careful attention should be paid to:
•
Quality of the power supply: low ripple, PFM or PSM systems should be
avoided (PWM converter preferred).
•
Capacity to deliver high current peaks in a short time (pulsed radio
emission).