Hi,

I need a sinusoidal frequency input where the frequency can be increased in step.

For example, 250MHz, then 251MHz, then 252MHz, and the list goes on until 450MHz.

How can I do it?

 

How accurate does the frequency need to be?

The easiest way is a programmable signal generator.

 

Google for "MHz huff'n'puff".

It's a silly name but a very clever concept, a simple digital circuit that allows "step tuning" and locking of an analogue RF oscillator in actual Hz steps.