Topic: Digital Circuits
Two signals $f_a$ and $f_b$ are given as input to EX-OR to measure phase difference. The average output voltage will be
- A. A triangular wave passing through the origin with a positive peak at $\pi/2$ and negative peak at $-\pi/2$
- B. A sawtooth wave passing through the origin
- C. A triangular wave strictly in the positive voltage plane bounded between 0 and V
- D. A sawtooth wave strictly in the positive voltage plane
Answer: A. A triangular wave passing through the origin with a positive peak at $\pi/2$ and negative peak at $-\pi/2$
Explanation: When two signals with the same duty cycle are applied to an EX-OR phase detector, the average output voltage $V_{avg}$ varies as a triangular function of the phase difference $\theta_e$. It reaches a positive maximum at a phase difference of $\pi/2$ and a negative maximum at $-\pi/2$.