Re: ADC questions
Hi !
Helping you on the tuned LC circuit, the formula is:
Resonant Frequency = 1 / ( 2 * PI * √ (L * C)
What results in: 1 / ( 2 * 3.14159 * (0.010 * 40E-12)^0.5 ) = 251.646 kHz
Good clue for the Quantization Error question is to read the documente "ABCs of ADCs" available at National site. A piece from this article:
"The maximum error we have here is 1 LSB. This 0 to 1 LSB range is known as the “quantization uncertainty” because there are a range of analog input values that could have caused any given code and we are uncertain at to exactly what that input voltage was. The maximum quantization uncertainty is also known as
the “quantization error”. This error results from the finite resolution of the ADC. That is, the ADC can only resolve the input into 2n discrete values. The converter resolution, then, is 2n. So, for an 8 Volt reference (with a unity gain factor), a 3-bit converter resolves the input into VREF/8 = 8V/8 = 1 Volt steps. Quantization error
then is a round off error.
But an error of 0 to 1 LSB is not as desirable as is an error of ±1/2 LSB, so we introduce an offset into the A/D converter to force an error range of ±1/2 LSB.
Digital Output "
Correcting the coleague response:
The binary number at output of AD converter will be: 0000101000 which means 40 in decimal. In fact at 10 bits resolution, you have 1023 steps and 1024 points. The range is 5V - 0V = 5V
Each step has 5V/1023 = 0.00488759V
So 0.2 / 0.00488759 = 40.92 which turns into 40 integer or 0000101000 binary.
Here you can see that the error is 0.92 * 0.00488759 = 4.49mV.
The quantization error can reach 4.88759mV or 1 LSb