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GATE 2025 IN – Question 40

Digital Electronics · Sequential logic and counters · 2 marks · Multiple choice

The digital circuit shown has clock frequency 12 MHz. Its output F frequencies for Control = 0 and Control = 1, respectively, are

Diagram for GATE 2025 IN question 40
  1. 4 MHz and 6 MHz
  2. 6 MHz and 4 MHz
  3. 3 MHz and 4 MHz
  4. 3 MHz and 6 MHz

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Show answer and explanation

Correct answer: (A) 4 MHz and 6 MHz

Explanation

Let states be the two Q outputs a,b.

The next-state equations are a+=NOT b and b+=(NOT b)(a+Control).

With Control=0 the recurrent sequence 00→10→11→00 has period three.

With Control=1, b toggles every clock, giving period two.

Thus output frequencies are **4 MHz and 6 MHz, A**.