Question

In a D/A converter, the usual way to solve the glitch is to use deglitcher. How is the Deglitcher designed?

(a) By using a low pass filter

(b) By using a S/H circuit

(c) By using a low pass filter & S/H circuit

(d) None of the mentioned

This question was addressed to me in an interview.

This intriguing question originated from Digital to Analog Conversion Sample and Hold topic in chapter Sampling and Reconstruction of Signals of Digital Signal Processing

Answer 1

The correct answer is (b) By using a S/H circuit

Easy explanation: The usual way to remedy this problem is to use an S/H circuit designed to serve as a “deglitcher”. Hence the basic task of the S/H is to hold the output of the D/A converter constant at the previous output value until the new sample at the output of the D/A reaches steady state, and then it samples and holds the new value in the next sampling interval. Thus the S/H approximates the analog signal by a series of rectangular pulses whose height is equal to the corresponding value of the signal pulse.