Telecommunication- telephone

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Slide 1

The Telephone

transmitter

loudspeaker

(Sound energy to

electrical energy)

(Electrical energy

to sound energy)

Slide 2

Printed circuit board of the telephone

Slide 3

An Older Telephone

Slide 4

Using an oscilloscope

1) Quiet sound, low frequency:

2) Quiet sound, high frequency:

3) Loud sound, low frequency:

4) Loud sound, high frequency:

Slide 5

Telecommunication Optical Fibres

The law of reflection.

When a ray of light bounces off a mirror , the angle going in equals the angle coming out.

The line at right angles to the mirror is called the normal.

Slide 6

Optical Fibres

When light is incident on a glass surface, refraction or bending of the light takes place.

The light comes out of the glass.

This however is dependent on the angle i.

Slide 7

Finding the Critical Angle…

1) Ray gets refracted

4) Ray gets internally reflected

3) Ray still gets refracted (just!)

2) Ray still gets refracted

Slide 8

Optical Fibres

Optical fibres are made of thin flexible glass threads.

They are about the size of a human hair.

The fibres have a protective coating which keeps the light inside the fibre.

Slide 9

Satellites

Interactive summary.

Satellites which orbit the earth every 24 are called satellites.

They are above the _ point on the _ .

Satellites use dishes to _ the microwave signals.

The microwave signals travel in _ lines.