Interference And Sensitivity; Power Supply Noise; Interference From Other Wireless Devices - Sierra Wireless MC5725V Hardware Integration Manual

Note: These modules are based
on ZIF (Zero Intermediate
Frequency) technologies; when
performing EMC
(Electromagnetic Compatibility)
tests, there are no IF
(Intermediate Frequency)
components from the module to
consider.
Note: Values in this guide are
taken from the appropriate
product specification documents
(PSDs) (listed in
documents
,
case of a discrepancy between
this document and the relevant
PSD, use the value listed in the
PSD.
Rev 1.8.2 Oct.08
In the event of a discrepancy in values between this guide and the Product Specification Document (PSD), the PSD takes precedence.
Related
page 8) — in the
Proprietary and Confidential
MC8780 / M C8781 / M C8785V / M C8790 / M C8790V /
•
M C8791V / M C8792V — Use the AT command
disable receive diversity or
diversity.

Interference and sensitivity

Several sources of interference can affect the RF performance
of the module (RF desense). Common sources include power
supply noise and device‐generated RF.
RF desense can be addressed through a combination of
mitigation techniques and radiated sensitivity measurement.

Power supply noise

Noise in the power supply can lead to noise in the RF signal.
The power supply ripple limit for the module is no more than
200 mVp‐p 1 Hz to 100 kHz. This limit includes voltage ripple
due to transmitter burst activity.

Interference from other wireless devices

Wireless devices operating inside the host device can cause
interference that affects the module.
To determine the most suitable locations for antennas on your
host device, evaluate each wireless device's radio system,
considering the following:
Any harmonics, sub‐harmonics, or cross‐products of signals
•
generated by wireless devices that fall in the module's Rx
range may cause spurious response, resulting in decreased
Rx performance.
The Tx power and corresponding broadband noise of other
•
wireless devices may overload or increase the noise floor of
the module's receiver, resulting in Rx desense.
The severity of this interference depends on the closeness of
the other antennas to the module's antenna. To determine
suitable locations for each wireless device's antenna,
thoroughly evaluate your host device's design.
RF Integration
!RXDEN=0
!RXDEN=1
to enable receive
to
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