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 : Qualcomm Incorporated (QCOM) -- Ignore unavailable to you. Want to Upgrade?

To: DaveMG who wrote (33078)	6/24/1999 11:41:00 AM
From: Clarksterh	Read Replies (2) \| Respond to of 152472

Dave - It's my understanding that WCDMA(Direct Sequence) requires one band 5mhz wide and that CDMA2000 will use 3x1.25 mhz(ie 3 multi 1.25mhz carrier) channels. TDD will use a block of yet another dimension. The W-CDMA non-TDD mode requires 2 different bands of 5 MHz separated by, perhaps, 30 to 50 MHz. One of the bands would be exclusively the forward link, and the other would be exclusively the reverse link. CDMA-2000 non-TDD mode requires 2 different bands of at least 1.25 MHz separated by 30 to 50 MHz. Again, one band would be exclusively the forward link and the other would be exclusively the reverse link. The advantage of this MC mode is that they could also operate well with 2 different 2.5 or 3.75 MHz bands as well. The reason that the forward and reverse links have to be separated by large amounts is that it is important that the phone is not trying to transmit and receive on the same frequencies at the same time since the transmitted signal would swamp the signal they were trying to receive. (Try talking to your friends at the same time you are trying to listen to them, and it is essentially impossible when they are fifty feet away. At thousands of feet, as with a cell phone, it is much much worse. But if you take turns talking (i.e. like TDD) it becomes possible.) Note that both CDMA-2000 and W-CDMA have a TDD mode, but it sound like these will be removed from the MC and DS modes of 3g and combined to be the third mode of 3g. Clark