What is the minimum data rate ?

Discussion in 'General Electronics Chat' started by sama3505, Jun 10, 2016.

1. sama3505 Thread Starter New Member

Jun 10, 2016
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0
Include the all equations how to do this.
What is the minimum data rate needed if you wish to sample a 10V analogue signal with at least 20 mV precision and 512 samples per second?

2. Marley Member

Apr 4, 2016
224
54
10V divided by 20mV = 500 steps minimum in the ADC.
500 steps could be represented by 2^9 bits (actually = 512). So a 9-bit binary value.
Transmitting 9 bits 512 times a second = 4608 bits per second.
This is an absolute minimum. In reality, there would have to be extra bits transmitted for timing and identification.

sama3505 likes this.
3. sama3505 Thread Starter New Member

Jun 10, 2016
18
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so if we get 30 steps ,are we getting it as 2^5 =32 ,so its a 5 bit binary value ? right?
and did you multiply that 10v/20mv =0.5 x 100 as well ?

Apr 5, 2008
17,121
3,001
Hello,

You have to take the mili in account.
It will be 10 / 0.02 = 500.

Bertus

5. Marley Member

Apr 4, 2016
224
54
Correct, 30 steps can be represented as a 5-bit binary value.
With 30 steps, the resolution will only be 10V / 30 = 0.333V (or 333mV).
So for more resolution you need more steps and more bits. To more accurately represent a changing analog value you need:
• more steps = more bits
• sample more often = more samples per second
So, more accuracy = greater data rate. This is one of the first rules of information theory.

6. sama3505 Thread Starter New Member

Jun 10, 2016
18
0
Thanks

can you have a look on this problem as well.