HF/VHF Synthesizer.

In general if I was to do this from scratch, I would use a PLL synthesizer controlled with a pic or some other microcontroller chip. To get to the right frequencies you want, you can use frequency multipliers and dividers as necessary. I haven't looked to see what chips would be best suited for your use, and I am sure there are many. It is less likely but also possible that you may find a chip that has much of this built in. Perhaps someone who is currently doing RF design could suggest part numbers.

Go to www.analog.com and search for synthesizer. You can design a circuit for yourself if you wish but these days you can get it all in one chip for practically nothing so there is little reason to unless you just want the education. Of course your requirements may drive you to do it yourself but I don't thing you should need to. You could almost use a TV tuner chip to cover the range you need except you are a little to low on the low end but it might be that all you would have to do is lower the base frequency since it would also go much higher than you upper frequency.

Thanks For your Comments,

I am out of station thats why I couldnt able to respond immidiately,

I saw TV tuner Chips, Most of them have a step size of around 50KHZ, is there any way to reduce this?

I don't know but suggest you study the data sheets. Perhaps you could lower the system clock but that may mess with other features. Maybe you could feed the system clock from a source that could be varied by some amount then you could use that as a fine adjustment to get +/- 25 kHz around each step.