In order to obtain repetitive pulses of unequal mark space durations one can use:1. A voltage comparator fed with a triangular wave signal and a dc voltage.2. An astable multi-vibrator.3. A mono-stable multi-vibrator fed with a square wave input.

In order to obtain repetitive pulses of unequal mark space durations o

1.	In order to obtain repetitive pulses of unequal mark space durations one can use:1. A voltage comparator fed with a triangular wave signal and a dc voltage.2. An astable multi-vibrator.3. A mono-stable multi-vibrator fed with a square wave input.
A.	1 and 3 only
B.	1 and 2 only
C.	2 and 3 only
D.	1, 2 and 3
Answer» B. 1 and 2 only