DataNotes - 1 Here are additional dictionary definitions of...

Info icon This preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
1
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Here are additional dictionary definitions of data. Notice the third definition, it restricts data to digital data. 2
Image of page 2
I n a broad sense, data doesn’t have to be digital. Analog data is data represented in continuous form. We are not trying to get into an argument whether matter is continuous or discrete. Quantum physics, Heisenberg’s uncertainty principle, and the dual wave/particle aspect of light you learn about them in a different class. 3
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Here is an example of continuous data. These color photographs were taken 100 years ago by Russia’s photographer to the tsar. Are they data? Of course, they provide a lot of and important information about those times. Are they digital? No. No pixels yet. It’s even before Kodak. Notice that they are color photographs. How were they taken? Prokudin took three slides, one with a red filter in front of the lens, one with a green, and one with a blue filter. Then put the three slides on top of each other, place a bright (white) light behind them, and you project in color. RGB existed before color TVs and pixels. Why does the river look like it is covered with a film of oil? Pollution? No, of course not. Think of how the slides were taken. 4
Image of page 4
Here are additional examples. Music has of course been recorded with analog devices. 5
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Electronics was also analog at the beginning. 6
Image of page 6
What are the shortcomings of analog data? Storage is inefficient big volume, small amount of data. Modifying the level of detail is not easy. Consider Prokudin’s photos. How could he have obtained a smaller photo from a large photo? He probably would have needed to project the large photo, then take a picture of the projection using smaller film, etc. Modifying data level of detail is essential, because not all applications need the data at the highest level of detail all the time. Transmitting analog data is also inefficient a little bit of analog data consumes a lot of bandwidth. A few years ago, TV broadcasts switched from analog to digital. Why? In order to be able to have more channels. Replication is another huge challenge. Every time you copy analog data quality goes down. For example recording from a VCR tape to another VCR tape lower quality. That’s why you need to always use the master tape as source. This slows down replication. Instead of being able to replicate from the ever increasing number of copies, you have to always go back to the master tape. 7
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
To overcome these disadvantages, the world moved to digital data. Digital data is data represented in discrete form, using numbers. For example, for digital music, I encode with a number what the music sounds like every millisecond. Since a millisecond is a very short time interval, all these values are a good approximation of the overall music.
Image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern