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FCC PART 15, SUBPART C, SEC. 15.247 - DIRECT SEQUENCE SPREAD SPECTRUM TRANSMITTERS
PCMCIA Wireless LAN Card, Model WL-211F
Theoretical Process Gain for CCK Modulation
In the case of CCK modulation at higher data rate, the Chip Rate/Symbol Rate (8 dB) is not an actual Process Gain since
it is a combination of both Process gain and Coding Gain. The formula true formula for Processing Gain calculation will
be based on the CW Jamming Margin. Please refer to the attached theoretical Process Gain calculation written by Mr.
Carl Andren at Intersil Corporation for details.
SCOPE:
This report presents the test procedure, test configuration and test data associated with a FCC Part
15.247 (e) Jamming Margin test for the indirect measurement of processing gain.
APPLICABLE REFERENCE DOCUMENTS:
5. "Operation within the bands 902-928 MHz, 2400-2483.5, and 5725-5850 MHz" Title 47 Part 15
section 247 (e) Code of Federal Regulations. (47 CFR 15.247).
6. "Report and Order: Amendment of Parts 2 and 15 of the Commission's Rules Regarding Spread
Spectrum Transmitters. Appendix C: 'Guidance on Measurements for Direct Sequence Spread
Spectrum Systems" FCC 97-114. ET Docket No. 96-8, RM-8435, RM-8608, RM-8609.
7. "HFA3861A Direct Sequence Spread Spectrum Baseband Processor"
Semiconductor Sector Preliminary Data Sheet, Melbourne FL, July 1999.
8. " M-ary Orthogonal Keying BER Curve",
TEST BACKGROUND AND PROCEDURE.
According to FCC regulations [1], a direct sequence spread spectrum system must have a processing
gain, G
of at least 10 dB. Compliance to this requirement can be shown by demonstrating a relative
p
bit-error-ratio (BER) performance improvement (and corresponding signal to noise ratio per symbol
improvement of at least 10 dB) between the case where spread spectrum processes (coding,
modulation) are engaged relative to the processes being bypassed. In some practical systems, the
spread spectrum processing cannot simply be bypassed. In these cases, the processing gain can be
indirectly measured by a jamming margin test [2]. In accordance with the new NPRM 99-231, if the
vendor has a system with less than 10 chips per symbol, the CW jamming results must be supported
by a theoretical explanation of the system processing gain.
ULTRATECH GROUP OF LABS
3000 Bristol Circle, Oakville, Ontario, Canada L6H 6G4
Tel. #: 905-829-1570, Fax. #: 905-829-8050, Email: vhk.ultratech@sympatico.ca, Website: http://www.ultratech-labs.com
•
Assessed by ITI (UK) Competent Body, NVLAP (USA) Accreditation Body & ACA/AUSTEL (Australia)
•
Accredited by Industry Canada (Canada) under ACC-LAB (Europe/Canada MRA)
•
Recognized/Listed by FCC (USA )
•
All test results contained in this engineering test report are traceable to National Institute of Standards and Technology (NIST)
CARL ANDREN
INTERSIL CORPORATION
JANUARY 11, 2000
CANDREN@INTERSIL.COM
321-724-7535
Page 47
FCC ID: MXF-WL211F
Harris Corporation
File #: GTT-013FTX
March 17, 2000
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