Which transistor should i use?

[Thomas0zero]

I need some circuitry help for something i have in the making.

I need a switch that will be receiving a pulsing signal and i need it to switch every time it receives a signal. For every 2 signals i only want the destination to receive one.

NO SIGNAL
SIGNAL (Sends current through switch then the switch goes to the switch off position)
NO SIGNAL
SIGNAL (signal is blocked but now the switch goes to the on position)

repeat

It also has to switch quickly. The signal will be under 12v. I need the output voltage to stay the same.

I was told i needed a transistor but that could be wrong.