Well, an ADC is an analog-to-digital converter. The 6534 is just a digital board. So on that basis alone, the answer is no, you can't use it to test linearity of an ADC with that board. I have no idea what you mean by "with agilent GPIB". This is somewhat meaningless, as it doesn't refer to anything.
As for VI examples to test ADC, this is completely dependent on the hardware you have.
I would suggest contacting your local NI sales office, as they will be capable of helping you pick out the right hardware for what you have and need to do.
