OCR GCSE Computer Science 1.2 Sound

What is sound?

• Something that is picked up by a microphone when generated by air.

• A wave of air that, when it hits the ear, produces a noise.

• Vibration that propagates as an audible wave of pressure through the air

• The level of air moved when someone speaks or uses a microphone.

A sound is analogue?

• True

• False

• Sometimes

Analogue to Digital Conversion is...

• The conversion of analogue signals so that we can hear them

• The conversion of an analogue signal into a digital signal so that it can be stored on a computer.

• Changing a sound file into something we can hear when it is played through a speaker.

• Saving a sound file after we have recorded it so that we can get it back later.

What is the Sample Rate?

• How many times we have to play a sound in order for it to be high quality.

• The speed of a signal going into a computer or microphone

• How many different samples we take of a file.

• How often per second we sample an analogue sound

What is Bit Depth

• The file size of the sound when saved in digital form

• The amount of times per second we take a snapshot of a sound

• The amount of detail captured with each sample of a file

• How many times we sample a sound

If we record two sound waves - 1 - with a high bit rate and 2 with a low bit rate. Which will have the larger file size on disk?

• 1

• 2

How many samples are taken of a sound wave each second if the sample rate is 50000Hz?

• 5

• 50

• 50000

• 500000

The higher the sample rate, the better the quality

• True

• False

• Sometimes

Draw an example of an analogue wave

Which of these numbers is represented by 4 bits?

• 10111

• 00101

• 0100

• 10011001