@shorai In my opinion the colors are wrong, but the connections are correct.or VCC should be red or GND should be black
TTL should be yellow
The frequency is typically 1kHz (not exactly but close enough) so your pulse width is 1ms. The pulse time would be 0 for 0% power, it is always at 0V, and at 100% power it would be 1ms at 5V (or thereabouts). 50% power would be 0.5ms at 5V and 0.5ms at 0V, square wave which would measure around 3.2V on a volt meter (RMS).