RET 2013:

INFORMATION IN

RADIO WAVES Ken Jacobs

Tim Scaduto

Fundamentals of EM spectra with emphasis on radio frequencies

History of radio astronomy

Information theory and Remote Sensing

Information transmitted through radio

Natural sources of radio

Technology of radio transmission

CORE UNITS

INFORMATION

THEORY

The foundation of

telecommunications

LEARNING OBJECTIVES

At the end of this unit students will be able to:

Communicate technical information about how some technological

devices use the principles of wave behavior and wave interactions with

matter to transmit and capture information and energy.

Summative assessment:

Students will look at a case study of radio astronomy and provide a

technical report on the strategies for investigating the radio emissions of

Jupiter.

WHICH OF THESE IMAGES

CONTAINS INFORMATION

your ideas? information - transfer of ideas,

forces, patterns, properties,

energy,

WHAT DO WE MEAN BY THE

TERM 'INFORMATION'

Claude Shannon

(1906-2001)

inventor of information theory and

modern telecommunication

SENDERS AND RECEIVERS

• The amount of information in every symbol of a message can be

quantified as the entropy of the message.

• The transmission channel has rules dependent on the physical

properties of the signal, source, and medium.

INFORMATION CONCEPTS

(LEARNING OBJECTIVES)

With your teammate:

o Have one person think of number between 0-100

o record the number of yes/no questions required to guess the number

o repeat for a number between

• 0-1000

• 0-1,000,000

• any whole number

o guess a sequence of numbers in a pattern

CODING WARM UP

NUMBER OF GUESSES PER TEAM

Team 1-100 1-1000 1-

1,000,000

sequence sentence

1

2

3

Guess a sentence

rules:

• Your group will be given a sentence of four to six

words with each of the letters (including spaces)

as unknowns.

• Your job is to guess the sentence exactly by asking

yes/no questions only.

• examples

o 'is this letter a b?'

o 'does it come before m in the alphabet?'

GAME 1: MEASURING

INFORMATION CONTENT

You were each given a different sentence

did they each contain the same amount of information ?

Why did one have more information than another?

SCORING/REFLECTION

GAME 2: VINCENT-PHIL-SHEP

Rules:

• The game is played with a two player team

o one player is the robot and the other the navigator

• Each team must devise a way for the navigator to

manipulate the robot accomplishing a simple (or not so

simple) task using just three words,

Vincent, Phil, Shep

• You have approx. 30 minutes to devise your strategy

o here are some practice tasks:

• easy: pick up an object, rotate, ....

• medium: clap your hands, touch your nose

• hard: find a bottle, do a forward role

GAME 2: VINCENT-PHIL-SHEP

Make an analogy to information transmission

What is the transfer channel?

What is the information?

What are the rules of the transfer channel and how did it affect the time and

accuracy of your task?

Describe your coding strategy, strengths? Weaknesses?

GAME 2: REFLECTION

Rules

• One student is given a copy of text

• That student must re-write the text using only uppercase

letters or numbers and spaces

• The goal is to use as few symbols as possible

• Once completed the other partner must reconstruct the

message losing 20 pts for each incorrect word.

• the score is 1 pt for every character that was saved.

GAME 3: TEXT MESSAGING GAME

You are given a sentence by your instructor and the only way to

transmit the information to your partner is by knocking on the door.

You have approximately 20 minutes to devise a scheme for your

transmission

GAME 4: THE KNOCKING GAME

Information is dependent on what you already know

Moving information requires a transmission channel that has rules

Rules of the transmission channel requires encoding the message

somehow.

TAKE HOME MESSAGE

You can only modify 4

things to send a message

Amplitude

Frequency

Phase

Polarization

These rules correspond to

the limited words available

in the games transmission

channel

ELECTROMAGNETIC RADIATION (EMR) AS A

TRANSMISSION CHANNEL HAS “RULES”

CONTRIBUTIONS OF INFORMATION

THEORY

Information Theory

Natural Science

Electrical engineering

Computer Science

?

Astronomers were some of the

first scientists who recorded data

over time and made models that

predicted the motion of the

objects they saw

In order to ‘prove’ their theories

they had to use observations that

were made remotely.

There was no way to directly

observe the materials of the moon

or mars … YET!

ASTRONOMY AS A FIRST SCIENCE

As the nature of the physical world was researched and developed,

new findings would allow us to conduct different experiments with

the light gathered from night sky objects.

Examples:

Knowledge about optics and the reflection/refraction of light allowed for the first

telescopes

Knowledge about the nature of light as a continuous spectrum allowed us to view

objects and derive their temperature.

Knowledge of the quantum mechanical structure allowed astronomers to develop

and understanding of the composition of materials I both luminous and non-

luminous

DIRECT OBSERVATIONS APPLIED TO

REMOTE OBSERVATIONS

ENGINEERED TRANSMISSIONS

Your eyes are the original remote

sensing detector!

We collect visible band EMR

Just like our eye, manufactured sensors

must all be build to detect changes in

the incoming radiation.

Most often we want to create maps or

images of the variations in order to look at

light and dark patterns which could tell us

something about the source.

REMOTE SENSING

PRIMER

http://en.wikipedia.org/wiki/Image:Mimas_moon.jpg

Passive sensing detects

radiation from natural

sources.

Either directly from source or

reflected/refracted by objects

or other medium

Active sensing requires a

source with known

properties be generated

and the effects of

interactions with a target

are observed at the

detector.

ACTIVE VS. PASSIVE REMOTE

SENSING

CASE STUDY: FINDING COLD

HYDROGEN IN SPACE

Information can be quantified and the amount depends on what you

already know about the message

Information carried in radio waves as a transmission channel can be

modified in 4 ways: Amplitude, Frequency, Phase, and, Polarization.

In formation in radio waves from natural sources can help us

understand the properties of the source, the objects they interact

with, and the medium through which they are travelling.

The technique of collecting information form distant objects is called

remote sensing

May be active, we send a signal and measure the results of interactions with target

Passive, look and the signals contained in natural sources and infer properties of

the source, interacting objects, or the medium.

CONCLUSION

Refer to the RET 2013 Unit: Natural Sources of Radio to discover

how radio science has increased our understanding of how the

universe works.

FOR FURTHER STUDY