I'd like to make a circuit that essentially produces very brief bursts of an RF signal, for example RF at 10MHz to 200-300MHz bursts of tens to hundreds of nanoseconds. For example this could be just one half of a sine wave at 10MHz, or for a few cycles of a 100MHz signal.
I'm familiar with some techniques for doing amplitude modulation (eg: varying the supply voltage of a linear amplifier), but I don't know of any way to do amplitude modulation this fast, or with 100% modulation depth.
The output should also be synchronized with the phase of the RF carrier in a predictable way, so it could always get a complete half-sine, rather than a random portion of a sine each time.
At the moment I'm imagining some kind of fast switch that diverts an RF oscillator to the output or to a dummy load. This is unfortunately not synchronized. Is there a better way of doing this? Perhaps something from ultra-wideband (UWB) type circuits?