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Tue May 5 09:47:12 EDT 2015
Slept well, although I could have used another hour. Rainy, but otherwise pleasant weather.
Dentist appointment today at noon.
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Dentist appointment went well. No problems. Next cleaning November 10th at noon.
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This is a great couplet from Auden's "As I Walked out One Evening":
Time watches from the shadow
And coughs when you would kiss.
Questions:
With the marketing debasement of the word "broadband", I've forgotten what it really means. Broadband vs baseband?
http://www.pearsonitcertification.com/articles/article.aspx?p=1358404&seqNum=3
quote:
Baseband
Baseband transmissions typically use digital signaling over a single wire; the transmissions themselves take the form of either electrical pulses or light. The digital signal used in baseband transmission occupies the entire bandwidth of the network media to transmit a single data signal. Baseband communication is bidirectional, allowing computers to both send and receive data using a single cable. However, the sending and receiving cannot occur on the same wire at the same time.
Note: Ethernet and baseband
Ethernet networks use baseband transmissions; notice the word "base"—for example, 10BaseT or 10BaseFL.
Using baseband transmissions, it is possible to transmit multiple signals on a single cable by using a process known as multiplexing. Baseband uses Time-Division Multiplexing (TDM), which divides a single channel into time slots. The key thing about TDM is that it doesn't change how baseband transmission works, only the way data is placed on the cable.
Broadband
Whereas baseband uses digital signaling, broadband uses analog signals in the form of optical or electromagnetic waves over multiple transmission frequencies. For signals to be both sent and received, the transmission media must be split into two channels. Alternatively, two cables can be used: one to send and one to receive transmissions.
Multiple channels are created in a broadband system by using a multiplexing technique known as Frequency-Division Multiplexing (FDM). FDM allows broadband media to accommodate traffic going in different directions on a single media at the same time.
/quote
For an example of broadband, it used to be the case that, with cable TV, each channel occupied a different frequency on the wire, so when you changed channels, it was just like changing stations on an FM radio tuner. With the advent of digital cable TV, I suspect it's a little more complicated; there may not be a 1:1 correspondence between frequency range and TV channel. Or maybe there is; maybe the channels can just be packed more densely with digital signaling....
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