Netgear NM7371 用户手册
NM7371 Hardware Integration Guide
12
Proprietary and Confidential
2400338
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 performance.
high levels of broadband or spurious noise can degrade the module’s performance.
•
Connecting cables between the module and the antenna must have 50
impedance. If the impedance of the module is mismatched, RF performance is
reduced significantly.
impedance. If the impedance of the module is mismatched, RF performance is
reduced significantly.
•
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.
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.
Ground connection
When connecting the module to system ground:
•
Prevent noise leakage by establishing a very good ground connection to the module
through the host connector.
through the host connector.
•
Connect to system ground using the two mounting holes at the top of the module.
•
Minimize ground noise leakage into the RF.
Depending on the host board design, noise could potentially be coupled to the
module from the host board. This is mainly an issue for host designs that have
signals traveling along the length of the module, or circuitry operating at both ends
of the module interconnects.
Depending on the host board design, noise could potentially be coupled to the
module from the host board. This is mainly an issue for host designs that have
signals traveling along the length of the module, or circuitry operating at both ends
of the module interconnects.
Interference and sensitivity
Several interference sources can affect the module’s RF performance (RF desense).
Common sources include power supply noise and device-generated RF.
Common sources include power supply noise and device-generated RF.
RF desense can be addressed through a combination of mitigation techniques (
on page 13) and radiated sensitivity
measurement.
Note:
The NM7371 is 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.
components from the module to consider.
Interference from other wireless devices
Wireless devices operating inside the host device can cause interference that affects
the module.
the module.
To determine the most suitable locations for antennas on your host device, evaluate
each wireless device’s radio system, considering the following:
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.
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.
overload or increase the noise floor of the module’s receiver, resulting in Rx
desense.