Radiated Emissions; Radiated Sensitivity Measurement; Audio Interfaces - Sierra Wireless AirPrime SL808 Series Product Technical Specification & Customer Design Manuallines

Rev 1 Dec.10 Proprietary and Confidential - Specifications subject to change
• RF trace and cable connecting the pin to the antenna should be of low loss
(<0.3 dB)
• Antenna connected on the ANT_PRM port should offer 2:1 or better VSWR in
order to maintain Tx power within +/- 2dB from the nominal power and the
VSWR could be 2.3:1 or better for the Rx band frequencies.
• Antenna connected on the ANT_GPS port should offer 3:1 or better VSWR in
order to maintain radiated sensitivity.
• Antenna location may affect RF performance. Although the module is
shielded to prevent interference in most applications, the placement of the
antenna is still very important—if the host device is insufficiently shielded,
high levels of broadband or spurious noise can degrade the module's perfor-
mance.
• Antenna cables should be routed, if possible, away from noise sources
(switching power supplies, LCD assemblies, etc.). If the cables are near the
noise sources, the noise may be coupled into the RF cable and into the
antenna.

4.8.5 Radiated emissions

The device alone meets all regulatory emissions limits when tested into a cabled
(conducted) 50  system. With antenna designs with up to 2.3:1 VSWR or worse,
the radiated emissions could exceed limits. These emissions must be tested with
the final antenna to ensure they pass. Examples of these limits would be FCC
Part 22 and Part 24, test case 12.2.1 for GSM (3GPP TS 51.010), and test case
4.2.2 for WCDMA (ETSI EN 301 511).
The system gain value affects both radiated power and regulatory (FCC, IC, CE,
etc.) test results.

4.8.6 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.
Most carriers require a certain level of receiver performance to ensure proper
functioning of the device on their networks. Although AirPrime soldered-down
modules have been designed to meet these carrier requirements, they are still
susceptible to various performance inhibitors.

4.9 Audio interfaces

The AirPrime SL808X Embedded Module supports two audio interfaces (analog
and PCM digital) and allows dynamic run-time selection of the appropriate
interface:
• Analog audio interface
• Digital audio interface (PCM)
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