Question

2. The finite conversion time of an A/D has serious consequences on the rate of change of signals presented for conversion. The A/D output will be in error if the input voltage changes more than one LSB during the conversion time of the A/D. Eq. 3 of the handout characterizes this change of the input signal as: ?V = TA (dVin/dt) Where TA is the conversion time of the A/D and dVin/dt is the derivative of the input voltage. For good A/D conversion without a sample and hold circuit ?V ? LSB of A/D

a. Determine the maximum ?V for good conversion for a 10-bit A/D with VFS = 5.0 V and a 20 ?s conversion time.

b. Determine the maximum frequency of a sinusoidal input whose peak-to-peak voltage is equal to VFS that can be input to the A/D and not exceed the ?V determined in part (a). c. Explain why a sample-and-hold circuit is often part of a reliable data acquisition system.

Answer 1