User's Manual

80-VF329-3 Rev. A 21 QUALCOMM Confidential and Proprietary
MAY CONTAIN U.S. EXPORT CONTROLLED INFORMATION
UNDP-1 Universal Notebook Data Platform User Guide RF Integration
The host PC is a hostile environment for RF transceivers, making the shields absolutely
necessary. Potential interference sources include the following:
■ Noise or ripple on the DC power supply voltage input lines, including transients due to
switching-mode power supplies or host operating mode changes.
■ High-speed digital logic transistions – The fast rising and falling edges include high
frequency harmonics that can fall into the UNDP Rx and/or Tx passbands. Host
circuits most likely to cause problems are the microprocessor, memory, and its
displays and display drivers.
■ Clocks – Also due to their high-speed transitions
■ Other wireless devices, whether integrated into the host PC or external, such as
WLAN (802.11) and Bluetooth devices. Transmit channels and their associated
wideband noise can jam the UNDP receivers, and even their LO frequencies, digital
logic, or clock signals can be disruptive.
Careful design is required to minimize the interference. UNDP-1 performance parameters,
such as receiver sensitivity and transmitter spurious signals, should be evaluated to
confirm adequate grounding and shielding, location of the UNDP antennas, and perhaps
even placement and routing of other host computer functions. This evaluation should be
performed for all UNDP-1 operating bands.
4.5 Antenna considerations
As mentioned in Section 4.4, the location of the antenna elements is critical to UNDP-1
RF performance. Routing the connecting coaxial cables could also impact UNDP
performance; they should be routed away from corruptive noise sources (like the
switching-mode power supplies, LCD assemblies, microprocessor, memory, etc).
Additional suggestions are provided in Antenna Design Guidelines for Laptop and
Notebook Computers (80-H2929-1).