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HUAWEI EM820W HSPA+ PC Embedded Module
Hardware Guide
4.4.2 Interference
Besides the antenna performance, the interference on the user board also affects the
radio performance (especially the TIS) of the module. To guarantee high performance
of the module, the interference sources on the user board must be properly controlled.
On the user board, there are various interference sources, such as the LCD, CPU,
audio circuits, and power supply. All the interference sources emit interference
signals that affect the normal operation of the module. For example, the module
sensitivity can be decreased due to interference signals. Therefore, during the design,
you need to consider how to lessen the effects of interference sources on the module.
To lessen the effects of interference sources on the module, you can use an LCD
with optimized performance, shield the LCD interference signals, shield the signal
cable of the board, or design filter circuits.
Huawei is capable of making technical suggestions on radio performance
improvement of the module.
4.4.3 GSM/WCDMA Antenna Requirements
The antenna for EM820W must fulfill the following requirements:
Table 4-5 GSM/WCDMA antenna requirements
GSM/WCDMA Antenna Requirements
Frequency range
Bandwidth
Gain
Impedance
Input power
VSWR absolute max
VSWR recommended
Furthermore, if the device is developed for US and/or Canada market, it must comply
with the FCC and/or IC approval requirements:
Issue 01 (2010-12-09)
Depending on the frequency band(s) provided by the
network operator, the customer must use the most
suitable antenna for that/those band(s)
70 MHz in GSM850
80 MHz in GSM900
170 MHz in DCS
140 MHz PCS
70 MHZ in WCDMA850
80 MHz in WCDMA900
140 MHz in WCDMA1900
250 MHz in WCDMA2100 band
Gain < 3dBi
50 Ohm
> 33dBm(2 W) peak power in GSM
> 24dBm Average power in WCDMA
<= 10:1
<= 2:1
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RF Specifications
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