dynamic range of an ADC

[preethi19]

Hi i am learning the basics of ADC. I understand the concept of resolution, samples and all. But how can i determine the Input frequency range that the ADC can function.
i found this online "I bought a Analog to Digital Converter but did not gave much attention to Dynamic range. The resolution is 12 Bit. Minimum input voltage is 0V and maximum is 5V. Additional info: It says it has 10Megasample per sec of sample-rate."

So i have details of the min and max input voltage range, resolution and sample rate too. How can i determine the frequency range. To know what is the lowest and highest frequency range i can have my input signal.

I found the above mentioned ADC details on this site https://electronics.stackexchange.com/questions/120590/how-to-find-the-dynamic-range-of-adc
Here they have calculated the dynamic range to be 72dB. But why dB. I thought dynamic range is the range of input values the ADC can take which is either range of input amplitude voltage (V) or input frequency range (in Hz). What does 72dB mean here. I read dB represents intensity which is amplitude. But then we have the max amplitude range that the input can go is 5V. Additionally how did they arrive at 72dB. 5/0.0012 gives 4098. I'm little confused here. Can anyone pls explain in simple terms. Thank you!!!

 

[KlausST]

Hi,

With an ADC you have a (vertical) resolution in voltage, LSB, bits...

and it has a (horizontal) resolution in time. (sample rate, sampling frequency..)

Both values are independent, don´t mix them.

****
For usual sampling: the analog input frequency must be limited to (below) half of the sampling frequency. (Read about Nyquist )

***
About db: you also asked in the other thread. Don´t double post.


Klaus

 

[chuckey]

The maximum output of 5V is made of 2^ 12 steps, so a signal of less then one step will not produce an output. If you are measuring AC, then in the absence of an input signal you have to bias the input to + 2.5 V, so the input can go positive and negative from this value. Also the ADC works on the peak signal so if you measure your input in RMS voltages, you have to make an allowance. So your 0 -> 5V ADC has a maximum input of 2.5/1.4 V RMS.
Frank