I'm expecting to be schooled here, but if I remember correctly, dB in isolation is the logarithmic expression of a ratio.
In the case of the 2-way splitter it would refer to the ratio of input level to level on a given outut from the splitter. No reference level needed. However, the "measurement" of the signal from the cable company would have to be in relation to some reference level. That reference level would be assumed or calibrated by the test equipment, and may be printed on the unit someplace. dBm, dBW, dB�V et al are needed when a specification or measurement is being compared against an established reference level (i.e. a "+4 dB" line level input to professional recording equipment is actually +4dBm - a specific power ratio). But it's OK to say a splitter costs 3.5 dB - you're describing the ratio of input signal to output. You can describe it as power or voltage and the numbers should still add up, at least if the loss is resistive or distributive in nature. DC >Cory Papenfuss wrote: > >> My only question is: >> 3.5 dB whats? dBm, dBW, dBuV, dBarbitrary_cable_number? >> >> | >> \ / >> >>> cable from (+3.5dB in) >>> cable co ------> 2-way splitter ------> cable modem >>> (+3.5dB | (0 dB) >>> measured) | >>> v >>> HPF (0dB) >>> | >> >> >> ...but I'm not one to pick nits... :) > >That would be dBarbitrary_cable_number_combined_with_my_ignorance... ;) > >The values are probably meaningless (I guess I should have gone farther >than just saying approximate/guesstimate :), but if nothing else should >show that everything connected to the cables (not to mention the cables >themselves) contributes to losses. > >Now I guess I have to go look up dBm, dBW, and dBuV... Too much to >learn. To little time. :) > >Mike > > >------------------------------------------------------- >SF email is sponsored by - The IT Product Guide >Read honest & candid reviews on hundreds of IT Products from real users. >Discover which products truly live up to the hype. Start reading now. >http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click >_______________________________________________ >ivtv-devel mailing list >[email protected] >https://lists.sourceforge.net/lists/listinfo/ivtv-devel -- -- | http://www.jimmiedave.com/ | | "Grease is great, | grease is good, | let us have some | on our fo-od" | | - Bruce Gibson ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_ide95&alloc_id396&op=click _______________________________________________ ivtv-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ivtv-devel
