measuring period

I'm trying to make a circuit that measures the period of a signal, ranging from 1ms to 10sec. Can you give me any ideas ? I have an idea, using 1kHz clock signal and some decade counters, but i need something to tell me when has elapsed one period of the unknown signal, so i should stop counting and display the time. Apparently using a trigger won't do it, since it will divide the frequency and i'll be measuring twice the period. Is my idea even close to the solution ? I'm a bit confused, and I don't have any experience with digital circuits.

The easiest way is to use a micro-controller, but it could be done in hardware using multiple chips.

Essentially you're building a frequency counter, and many already include this facility.

But where a frequency counter counts an unknown frequency in a set time, you want to count a known frequency for an unknown time. As you suggested, a 1KHz oscillator would be a good clock source, and give 1mS resolution.

A simple sequence of events would go like this:

1) Reset the counters:
2) Use the start of the pulse to gate the 1KHz oscillator to the counters.
3) Use the end of the pulse to close the gate to the oscillator.
4) The counters now contain the number of milliseconds the pulse was On for.
5) Display the counter values.

With a PIC you could do it all inside the PIC, a simple 16F628 and an LCD text module to display the result.