Radiated Sensitivity Measurement; Sierra Wireless' Sensitivity Testing And Desensitization Investigation; Ota Test Chamber Configuration - Sierra Wireless MC5725 Hardware Integration Manual

Rev 1.9.1 Feb.09
In the event of a discrepancy in values between this guide and the Product Specification Document (PSD), the PSD takes precedence.
Shield the host device. The module itself is well shielded to
•
avoid external interference. However, the antenna cannot
be shielded for obvious reasons. In most instances, it is
necessary to employ shielding on the components of the
host device (such as the main processor and parallel bus)
that have the highest RF emissions.
• Filter out unwanted high‐order harmonic energy by using
discrete filtering on low frequency lines.
• Form shielding layers around high‐speed clock traces by
using multi‐layer PCBs.
• Route antenna cables away from noise sources.
Radiated sensitivity
measurement
A wireless device contains many sources of noise that
contribute to a reduction in Rx performance.
To determine the extent of any desensitization of receiver
performance due to self‐generated noise in the host device,
over‐the‐air (OTA) or radiated testing is required. This testing
can be performed by Sierra Wireless or you can use your own
OTA test chamber for in‐house testing.
Sierra Wireless' sensitivity testing and
desensitization investigation
Most carriers require a certain level of receiver performance to
ensure proper functioning of the device on their networks.
Although the module has been designed to meet these carrier
requirements, it is still susceptible to various performance
inhibitors.
As part of the Engineering Services package, Sierra Wireless
offers modem OTA sensitivity testing and desensitization
(desense) investigation. For more information, contact your
account manager or the Sales Desk (see page 5).
Note: Sierra Wireless has the capability to measure TIS (Total
Isotropic Sensitivity) and TRP (Total Radiated Power) according to
CTIA's published test procedure.

OTA test chamber configuration

To make OTA measurements, a test chamber is required. A
full‐size anechoic chamber is not necessarily required.
Figure 3‐2 shows a small anechoic chamber manufactured by
Proprietary and Confidential
RF Integration
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