ADC Resolution and Resolution

QWE4562009

ADC Resolution and Resolution [Copy link]

 

ADC resolution and resolution
1. How to understand the effective resolution of ADC and the gain error of PGA? 2.
What does the resolution of 60000d mean?
3. Are the accuracy and resolution of ADC the same concept ?

lugl4313820

ADC resolution and resolution
1. How to understand the effective resolution of ADC and the gain error of PGA? 2.
What does the resolution of 60000d mean?
3. Are the accuracy and resolution of ADC the same concept ?

Are you asking about accuracy and resolution?

Precision refers to the error, which is the deviation of the measured value from the actual value.

Resolution refers to the number of bits of the ADC, which determines the scale of the ADC. For example, a 10-bit ADC is 2 to the power of 10, and so on. This is another netizen's answer, I hope it will be useful to you:

The accuracy is related to the entire system. For example, how many volts does your system measure for 1V?

If only the temperature drift of the reference voltage is considered

A system with a reference voltage of 2.048V and a 12-bit ADC measures a 1V DC input. Theoretically, it should be: m1=2.048/4096=2000. Then the actual voltage obtained based on this sampling value is: 2000*2.048/4096=1V

If the reference voltage changes to 2.5v, then the actual measured value is: 1638.4. Considering that the sampled value is an integer, the actual value may be 1638. Because the reference voltage is the "reference voltage" of the system (a bit confusing), then we think it is accurate, that is, we think it has not changed, so it should be 2.048v. In this way, the voltage calculated based on this sampled value is: 1638*2.048/4096=0.819v, and the error is: 18.1%, which is actually (2.5-2.048)/2.5=18.08% (because the sampled value is an integer, so this is slightly different from 18.1%)

From here we can see that although the minimum scale of the ADC has not changed, the accuracy is very poor. This can be corresponded to the commonly used ruler: the minimum scale of the ruler has not changed, but due to thermal expansion and contraction, the ruler has become longer (or shorter), so the size of the measured object is also wrong, but this ruler can still distinguish which of the two different objects is longer and which is shorter according to the minimum scale, but the absolute value is no longer correct. This is the relationship between the resolution and accuracy of the ADC

From the above example, we can roughly get the method of selecting the ADC reference source. Without considering the errors of other parts of the system, the measurement error = reference error (in fact, since other parts of the entire system are not ideal, the measurement error > reference error)

Assuming a 12-bit ADC, the resolution is 1/4096. If we want to achieve an accuracy of 1/4096, that is, for an actual 1v input, we hope that the measured result is between 0.999755859375 and 1.000244140625.
In this way, the error of the reference power supply is <1/4096. Assuming that our system operating range is 30℃, the corresponding temperature drift is: (1/4096)/30*1e6=8.13ppm/℃
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Copyright statement: This article is an original article by CSDN blogger "varding", which follows the CC 4.0 BY-SA copyright agreement. Please attach the original source link and this statement when reprinting.
Original link: https://blog.csdn.net/varding/article/details/19135249

lugl4313820

Also, please check after posting to see if the title is correct.

QWE4562009

lugl4313820 posted on 2023-4-10 07:16 Also, please check after posting to see if the title is correct.

It should be resolution and accuracy. Sorry.

QWE4562009

lugl4313820 Published on 2023-4-10 07:14 ADC resolution and resolution 1. How to understand the effective resolution of ADC and the gain error of PGA? 2. What does the resolution of 60000d mean? 3. The resolution of ADC...

I've seen this post, it's not very popular

QWE4562009

lugl4313820 Published on 2023-4-10 07:14 ADC resolution and resolution 1. How to understand the effective resolution of ADC and the gain error of PGA? 2. What does the resolution of 60000d mean? 3. The resolution of ADC...

However, due to thermal expansion and contraction, the entire ruler becomes longer (or shorter), so the size of the measured object is also wrong. However, this ruler can still distinguish which of two different objects is longer and which is shorter according to the smallest scale------------How can the accuracy remain unchanged despite thermal expansion and contraction?

QWE4562009

lugl4313820 Published on 2023-4-10 07:14 ADC resolution and resolution 1. How to understand the effective resolution of ADC and the gain error of PGA? 2. What does the resolution of 60000d mean? 3. The resolution of ADC...

8.13ppm/℃---------means that a temperature rise of 1° will result in a shift of 8.13 parts per million?

lugl4313820

QWE4562009 posted on 2023-4-12 18:40 8.13ppm/℃---------meaning that a temperature rise of 1° will result in a shift of 8.13 parts per million?

In layman's terms, resolution is the maximum scale you can get. Under the reference voltage, 10 bits is 2 times 10, divided into 1024 scales. If your reference voltage is 3.3v, the resolution of the ADC is 3.3/1024 = 3.2 millivolts. If your ADC is 16 bits, it is 3.3/65536 = 50 microvolts. The higher the number of bits, the higher the resolution. Under the same sampling rate, the higher the number of bits, the higher the sampling accuracy.

lugl4313820

QWE4562009 posted on 2023-4-12 18:40 8.13ppm/℃---------meaning that a temperature rise of 1° will result in a shift of 8.13 parts per million?

ADC is a complex thing. Some ADC chips can sell for tens of thousands of yuan, while some ADCs only cost a few cents. A good ADC can produce results with an error of a few microvolts.

模拟器新军

60000d---decimal

QWE4562009

[quote]lugl4313820 posted on 2023-4-12 22:49 In layman's terms, resolution is the maximum scale you can get. Under the reference voltage, 10 bits is 2 times 10, which is divided into 1024 scales. If your reference voltage is 10, the resolution is 10 times the 2 ...

I understand this.

QWE4562009

Simulator New Army published on 2023-4-13 15:05 60000d---decimal decimal

That is 60,000 copies.

EFT

Xiaobai came to learn, thanks for sharing, Laotie 6666666

H12315

CS1237 can float up with a breath of output. Normally it can be used as a 16-bit or 17-bit ADC. If it is higher, it needs to be shielded and temperature-controlled.