Engineering Specification
ES-3U5T-1B257-AA
EMC Design Guide for Printed Circuit Boards
Frame 11 of 78
Rev. A
10/01/2002
Printed copies are uncontrolled
2.3. Regulations and Standards
E/E devices on Ford products must comply with a variety of requirements mandated by:
·
Federal Communications Commission (FCC) regulations
·
Ford EMC specifications
·
European Community (EC) EMC Directive
Within the United States, the FCC is responsible for radio spectrum allocations and
assignments outside the federal government sector. FCC 15J is the FCC document that
controls the interference potential of electronic computing devices. A computing device
is defined as any electronic device or system that uses digital techniques. This
encompasses any device that intentionally generates and utilizes frequencies in excess of
10 kHz. The FCC regulates transmitters and receivers under a different rule.
Vehicle radios and remote controlled transceivers must comply with FCC regulations.
Most other E/E modules designed exclusively for a vehicle use, have Section 1
exemption from FCC regulations. However, Ford has a policy of voluntary compliance
for all modules.
The FCC regulates the amount of radiated EMI from an E/E device. Table 21 compares
the maximum radiated electric fields allowed by Ford and the FCC. The table shows the
electric field strength in dBµV/m and µV/m. FCC Class B limits are for consumer-type
computing devices.
Ford EMC requirement limits are derived from a variety of SAE, International Standards
Organization (ISO), and EC standards. The latest version of the primary Ford component
level EMC specification is available on line at
www.fordemc.com
.
By inspection of Table 21, it is evident that the Ford limits are much more stringent than
those of FCC; especially when one considers that FCC limits are measured 3 meters away
from the radiating device while Ford measurements are taken at 1 meter. The Ford limits
are more restrictive for two primary reasons:
·
Radiating devices on the vehicle are closer to radio transceivers on board the
vehicle
·
A vehicle contains many radiating devices