Error requirement of an ADC

[urian]

When I reading some books related to ADC, I find that while they were calculating the allowed minimum error referred to input of an ADC, some of them said that the error should be less than 1/2 LSB, which is the quantization noise, yet another declaimed that the error should be less than 2^-N or 1 LSB, which is the quantization noise floor. I wonder whether the two statements are valid or equivalent. If the 2nd is valid, does it assume that the FSR is 1 so that 2^-N is 1 LSB?


Regards
urian

 

[willis...]

When I reading some books related to ADC, I find that while they were calculating the allowed minimum error referred to input of an ADC, some of them said that the error should be less than 1/2 LSB, which is the quantization noise, yet another declaimed that the error should be less than 2^-N or 1 LSB, which is the quantization noise floor. I wonder whether the two statements are valid or equivalent. If the 2nd is valid, does it assume that the FSR is 1 so that 2^-N is 1 LSB?

For the most part this depends on your application. Some applications are much more sensitive to noise, while others can pass a relative amount of noise without affecting the system at all. You will want to investigate how much noise you think your system can handle. It also depends on the type of accuracy you are looking to get from your A/D. Less accuracy means that more noise can be allowed, and vice-versa; so bottom line it depends on your application.

Regards,
Willis

 

[urian]

Hi,Willis
Assuming that there is only one error in the ADC input and the accuracy requirement is that the error should not larger than the quantization noise, then which statement above is true?

Regards
urian