Integration Guide
Table Of Contents
- Important Notice
- Safety and Hazards
- Limitation of Liability
- Patents
- Copyright
- Trademarks
- Contact Information
- Revision History
- 1: Introduction
- 2: Power
- 3: RF Specifications
- 4: Regulatory Compliance and Industry Certifications
- 5: Acronyms
RF Specifications
Rev. 2 Dec.21 9 4118013
Determining the Antenna’s Location
When deciding where to put the antennas:
• 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 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 signifi-
cantly.
• 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.
Disabling the Diversity Antenna
Use the AT command !RXDEN=0 to disable receive diversity or !RXDEN=1 to enable
receive diversity.
Note: A diversity antenna is used to improve connection quality and reliability through redundancy.
Because two antennas may experience difference interference effects (signal distortion, delay, etc.),
when one antenna receives a degraded signal, the other may not be similarly affected.
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.
• 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.
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.
RF desense can be addressed through a combination of mitigation techniques (Methods
to Mitigate Decreased Rx Performance on page 10) and radiated sensitivity measurement
(Radiated Sensitivity Measurement on page 11).
Note: The MC7455 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.