Single chip microcomputer: basic concepts of a/d and d/a

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Preface

Today I'd like to explain to you , The basic concept of SCM ,A/D and D/A Basic concepts of .

A/D and D/A Basic concepts of

A/D It is the conversion from analog quantity to digital quantity , Rely on analog-to-digital converter (Analog to Digital Converter), abbreviation ADC.D/A It is the conversion from digital quantity to analog quantity , Rely on a digital to analog converter (Digital to Analog Converter), abbreviation DAC. The reason is exactly the same , It's just that the direction of conversion is different , Therefore, our explanation process is mainly based on A/D For example to explain .

Many students learned A/D In this part , Feeling is a difficult point , The concept is not clear , It's hard to master . Personally, I don't think the main reason lies in technical problems , But I don't know much about life . There are many, many things in our life A/D Example , Just not in the field of SCM applications , Now I'm going to take you all to understand A/D The concept of .

What is analog quantity ？ It refers to the quantity that the variable changes continuously within a certain range , That is, you can take any value within a certain range . Such as meter ruler , from 0 To 1 Between m , It could be any value . What is an arbitrary value , That is, it can be 1 cm, It can also be 1.001 cm, Of course 10.000„„ There are infinite decimals behind it . All in all , There are infinite intermediate values between any two numbers , Therefore, it is called the quantity of continuous change , That is, analog quantity .

The meter ruler we use is artificially marked with scale symbols , The interval between each two scales is 1 mm, This scale is actually our digitization of analog quantity , Because there is a certain interval , Not continuous , So we call it discrete in the professional field .ADC Is to play the role of expressing continuous signals with discrete numbers . Then we can use the meter ruler “ADC” To measure the continuous length or height of these analog quantities . As shown in the figure, a simple scale diagram of meter ruler .

We pour water into the cup , The water level will change with the amount of water poured . Now use this meter ruler to measure the height of the water level in our cup . The water level changes continuously , We can only read the height of the water level through the scale on the ruler , Get the digital information of the water level we want . This process , It can be simply understood as... In our circuit ADC sampling .

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