HS PH- EM and Technology- Analog versus Digital
Introduction: Imagine that you are asked to communicate information such as mass without a balance
or length without a meter stick. To communicate this information without these tools, you would need
to make analogies to other known ideas. For example, you could say something is as long as two sheets
of paper.
What kinds of comparisons would you make to communicate:
1. The mass of your textbook: is as heavy as 3 jbl speakers
2. The temperature of your milk at lunch: is as cold as a smoothie
3. The color of an object: ??
The clocks below are a common example between analog (left) and digital (right).
The clock on the left rotates its hands in a set path on a continuous scale. The digital clock is
programmed to change its display every 60 seconds. The time in between these steps cannot be read
like they can from the analog clock.
The digital clock uses binary code. This is a system of 0s and 1s. The 0 means OFF and the 1 means ON.
The ON and OFF are achieved by transistors which can switch on and off at fast rates (around 109 times a
second). These codes are then transmitted through wires or waves to our devices such as clocks,
computers, and displays in the form of characters, images or sounds.
Binary code uses just two numbers (0 or 1). Table A below shows How numbers 1 through 6 are
represented by binary code. Pay attention to the first time the 1 appears, followed by a 0 and then how
the 0 and 1s alternate. Code in 7 through 9.
TABLE A
Based 10
0
1
2
3
4
5
6
7
8
9
Binary (four
place holders
shown)
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
Look at the image of the digital clock. The numbers are made up of individual LED lights. These lights are
either ON (1) or OFF (2). The seven different segments of LED lights are shown below. Each segment has
been labeled with a letter A through G. Table B shows how a number in these seven segments would be
coded. Notice that if a 1 is in a letter that corresponds to that segment then that light will be ON. If there
is a zero, then that light segment will be OFF.
TABLE B
Binary Code (segments)
Number Displayed
A
B
C
D
E
F
G
1
0
1
0
1
1
1
1
1
1
1
1
1
1
0
0
0
1
1
1
1
1
0
1
1
1
0
1
1
1
1
0
1
0
1
1
1
0
1
0
1
0
1
0
0
0
1
0
1
0
1
0
0
1
1
1
1
0
1
1
0
0
1
1
1
1
1
0
1
1
Number
Displayed
0
1
2
3
4
5
6
7
8
9
Below is an image of a digital clock. Select a time and then use Table B to code for each digit. If the
corresponding letter is turned ON (1), then shade in that segment to show that is it lit. If the
corresponding letter is turned OFF (0) then leave that segment blank to show that the light is not on.
Time: 11:18
1st
2nd
3rd
4th
1st: 0110000
2nd: 0110000
3rd: 0110000
4th: 1111111
Music: Digitizing Music Through Graphing
Sound is a wave that varies continuously. The information for music can be stored as analog or digital. A
vinyl record is an example of an analog music storage device. The record has continuous spiral grooves
that rise and fall. As the record spins on the record player, the needle that fits into these grooves
vibrates as the grooves move under it. The vibrations are converted to an electric signal that is sent to
speakers.
Today, much of our music is digital. The original sound wave is stored as a collection of snap shots or
points from the original wave. This sequence is then stored as binary code. The digital information is
converted into an electric signal by the playing device (such as a smartphone) and sent to speakers.
Voltage (V)
The graph below represents the sound received by a microphone. The sound is then converted into
varying voltages based upon the continuously changing sound. The line represents the analog
interpretation and the dots represent the digital interpretation of the sound.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
Time (s)
21
Questions:
1. How can this graph be used to argue that analog recordings are more accurate than digital
recordings?
Analog recordings could be more accurate than digital recordings because digital recordings
waves are stored as a collection of snapshots.
2. How could the digital interpretation of this sound be improved?
It could be closer to the line of best fit (the analog line). This could be done by bettering
technology.