Ralph: Most LED luminaires for home replacement service now have a built-in "dimming" capability which is compatible with duty-cycle wall control switches (intended for the incandescent lighting era). The LED is driven by a constant-current switching power converter, but there is a "data path" around this converter which carries the duty-cycle information. This is applied to a fast switch that duty-cycle modulates the constant-current power converter output to the LED array, effectively proportioning the light output in accordance with the wall switch's control input. I imagine that the Li-Fi uses a similar, but faster, modulator scheme.
Ed Price WB6WSN Chula Vista, CA USA -----Original Message----- From: Ralph McDiarmid [mailto:ralph.mcdiar...@schneider-electric.com] Sent: Monday, December 11, 2017 8:47 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Li-Fi Sure, but fiber optics are special purpose, dedicate circuits. Isn't this fella talking about using existing luminaire in the home for data transmission? Maybe I don't know enough about his concept. Ralph McDiarmid Product Compliance Engineering Solar Business Schneider Electric From: John Woodgate [mailto:j...@woodjohn.uk] Sent: Monday, December 11, 2017 8:41 AM To: Ralph McDiarmid <ralph.mcdiar...@schneider-electric.com<mailto:ralph.mcdiar...@schneider-electric.com>>; EMC-PSTC@LISTSERV.IEEE.ORG<mailto:EMC-PSTC@LISTSERV.IEEE.ORG> Subject: Re: [PSES] Li-Fi LED light can indeed be modulated very quickly. Isn't that how fibre-optic cable works? John Woodgate OOO-Own Opinions Only J M Woodgate and Associates http://www.woodjohn.uk Rayleigh, Essex UK On 2017-12-11 16:20, Ralph McDiarmid wrote: I haven't studied it, but seems to me that one would need to modulate the light very quickly to get any sort of usable BAUD rate, unless you settle for transmission of text only. (like the good old Bell 202 modems over voice band land lines) Ralph McDiarmid Product Compliance Engineering Solar Business Schneider Electric - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
