"You need to design a fractional clock divider in RTL that divides a 1 GHz reference clock down to exactly 622.08 MHz (a real-world telecom frequency). You cannot use an analog PLL/DLL, only digital logic.
Constraints:
The divider ratio is non-terminating fractional (1 GHz ÷ 622.08 MHz ≈ 1.6077…).The output must have bounded jitter — no more than ±1 input cycle deviation from ideal.
The solution must be synthesizable and area/power efficient.
Hints:
"What happens if you alternate between two nearby integer divides — say ÷1 and ÷2 — to get an average?"
"Imagine you keep track of a remainder every cycle — what could you do with it?"
"The output clock edges don’t need to be perfectly uniform, but the deviation should never grow unbounded — how might you guarantee that?"
"What if I asked you to support not just ÷2.5, but ÷N/M in general — what structure could handle any fraction?"
"How would your design behave if the divided clock was used in a separate domain? Would you treat it as fully synchronous?"
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