[igCS] Analog and digital

[igCS] Analog and digital

Objectives

• Understand Analog and Digital Data

• ADC and DAC

• Microphone and speaker

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Analog Data

• Value is continuous

• Physical Data from the environment is analog

Digital

• Value is discrete (not continuous)

• Computers nowadays are digital

ADC (Analog to digital converter)

• Computer Processor cannot directly handle analog data

• But can only handle digital data

• ADC is to convert data from analog to digital

Multiple Choice

What is the black line representing?

• Analog Data

• Digital Data

• ADC

Multiple Choice

What is the pink line representing?

• Analog Data

• Digital Data

• ADC

How ADC works?

• Converting to digital means recording the value in discrete numbers

• We can "snapshot" the value in a regular interval and record as a series of value

• The technique is called "Sampling"

Microphone

• Microphone captures sound from environment (analog)

• an ADC converts the analog sound to computer digital format

• Sampling rate determines how frequent the data is recorded

Open Ended

The diagram on right shows higher sampling rate for a sound recording, while green line is the original sound in the environment. Explain how sampling rate affects the quality of sound.

DAC (Digital to Analog Converter)

• Computer can produce only digital output

• Output to physical world requires analog

• DAC is converting digital to analog output

DAC for speaker

• Computer music is digital

• A dedicated DAC chip is builtin to smartphone to convert digital music into audible sound waves (analog)

• The one on the picture is an external DAC to ensure higher quality of sound

Well Done!