Sierra Wireless MC5720, Hardware Integration Manual, Page: 17 / 30

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.
RF Integration
etc.). If the cables are near the noise sources, the noise may
be coupled into the RF cable and into the antenna.
Disabling the diversity antenna (MC5720)
If your host device is not designed to use the MC5720’s
diversity antenna, terminate the interface with a no ‐ connect.
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
Different wireless devices operating inside the host device can
cause interference that affects the module.
To determine the most suitable locations for each antenna 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.
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