http://chris.pirillo.com/what-is-dss/ News and Reviews! Geek, Internet Entrepreneur, Hardware Addict, Software Junkie, Book Author, Once TV Show Host, Technology Enthusiast, Shameless Self-Promoter, Tech Conference Coordinator, Early Adopter, Idea Evangelist, Tech Support Blogger, Bootstrapper, Media Personality, Technology Consultant, Thicker Quicker Picker Upper. Sat, 21 Nov 2009 16:51:42 -0800 http://wordpress.org/?v=2.8.5 hourly 1 http://chris.pirillo.com/what-is-dss/comment-page-1/#comment-531312 WiFi Packet Sniffing « Pirillovision Wed, 11 Jul 2007 15:43:55 +0000 http://chris.pirillo.com/2007/05/23/what-is-dss/#comment-531312 [...] Check out our other security videos: What is DSS? and Wireless Security Camera [...] [...] Check out our other security videos: What is DSS? and Wireless Security Camera [...]

]]> http://chris.pirillo.com/what-is-dss/comment-page-1/#comment-534058 michael spanos Thu, 24 May 2007 20:13:02 +0000 http://chris.pirillo.com/2007/05/23/what-is-dss/#comment-534058 Close, but no cigar. These newbs! ;-) Your explanation of FHSS (frequency hopping spread spectrum) is OK, but to me, DSS is Direct Sequence Spreading. There are crutial differences: FHSS can be used on either a digital or an analog signal and works as Heddy Lamar envisioned. More modern is the DSS where every bit of a digital signal is convolved (XOR'd if you are geeky enough) with a PN (pseudo-random number) sequence. A normal digitized signal is broad (frequency-wise) and this convolving spreads it even further to where it just looks like noise if you don't know the PN sequence. If you do know the sequence, when you apply it you get gain (amplification) equal to the sequence length applied. I believe Qualcom developed CDMA which first applies DSS and then applies FHSS to the "noise", using two different PN sequences! This way they can stack many users into any frequency segment; i.e. other users look like hopping noise to any particular user and little is lost because all users would use different random PN sequences. Close, but no cigar. These newbs! ;-) Your explanation of FHSS (frequency hopping spread spectrum) is OK, but to me, DSS is Direct Sequence Spreading. There are crutial differences: FHSS can be used on either a digital or an analog signal and works as Heddy Lamar envisioned. More modern is the DSS where every bit of a digital signal is convolved (XOR’d if you are geeky enough) with a PN (pseudo-random number) sequence. A normal digitized signal is broad (frequency-wise) and this convolving spreads it even further to where it just looks like noise if you don’t know the PN sequence. If you do know the sequence, when you apply it you get gain (amplification) equal to the sequence length applied. I believe Qualcom developed CDMA which first applies DSS and then applies FHSS to the “noise”, using two different PN sequences! This way they can stack many users into any frequency segment; i.e. other users look like hopping noise to any particular user and little is lost because all users would use different random PN sequences.

]]> http://chris.pirillo.com/what-is-dss/comment-page-1/#comment-534064 wylis Thu, 24 May 2007 18:26:31 +0000 http://chris.pirillo.com/2007/05/23/what-is-dss/#comment-534064 Chris your screensaver looks awesome on those dual monitors! Show us a demo some time with a media player visualization over both screens. Chris your screensaver looks awesome on those dual monitors! Show us a demo some time with a media player visualization over both screens.

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