Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Technology Stocks : The New Qualcomm - a S&P500 company -- Ignore unavailable to you. Want to Upgrade?

To: qdog who wrote (2710)	10/26/1999 10:52:00 AM
From: slacker711	Read Replies (1) \| Respond to of 13582

More info on V-OFDM.... fcc.gov 4. In its petition, Clarity submits that OFDM offers performance features not available in other digital modulations, specifically, the means for "achieving very high data rates in severe multipath conditions." OFDM is generated by the creation of multiple signals (carriers) within an authorized MDS or ITFS channel, each of which carrier is modulated with a portion of the information being transmitted. The signal modulating each of the carriers is typically a form of QAM, e.g. QPSK, 16-QAM or 64-QAM. The amplitudes and spacings of the carriers are configured such that the spectral energy of each carrier is significantly attenuated at the frequencies of each of the two adjacent carriers. The modulating QAM signals can be coded in order to be more robust in the presence of multipath propagation and/or interference, and Clarity proposes the use of its proprietary coding schema, designated Vector OFDM ("VOFDM"). Clarity retained the engineering firm of Hardin & Associates ("Hardin") to evaluate OFDM and determine its compatibility with, and potential for interference to, NTSC analog television signals. In an attachment ("Hardin Study") to the Clarity Petition, Hardin found, using laboratory tests, that OFDM "easily complies" with the interference protection requirements of the Commission's Rules. Hardin's laboratory tests were designed to insure that the OFDM emissions complied with the mask required for digital MDS/ITFS emissions. Hardin's conclusions were based on evaluations of two different OFDM waveforms, one with 256 carriers modulated by 4-QAM and the other with 4096 carriers modulated by 64-QAM.