Transmitter for microwave datalink.

Hi there.
I'm doing a project on transmitter for microwave data link, and i'm stuck on how to deisgn a pulse modulated crystall oscillator for a 4ghz microwave. please can you fellow forumers give me some links or possibly explain what to do in order to design this oscillator. P.s i've got fairly strong electronic knowledge, but little or no knowledge in microwave and rf designing.
Any little help will be most appreciated.

Best wishes.
Claudio.

What is your modulation plan?
What is the data rate?

Thanks for replying, i don't really have any plan with regards to the modulation, but i'm more likely to be using pulse width modulation to turn the carrier frequency on and off (I'm definitely in dark in this section). To answer your 2nd question, i'm going to be using low data rate since i will be transmiting audio.
Saying that i've got little knowledge about the whole thing any suggestion or help will be appreciated.

crystal oscillators do not work at 4 ghz. you will need a microwave VCO, and "phase lock it" to a crystal oscillator.

4 Ghz is not an approved "license free" frequency band anywhere in the world, so you will either need to get a license, or move your operating frequency. 880/915 MHz, 2.45 ghz or 5.9 ghz are possible bands, IF you meet your country's emissions requirements.

4 Ghz is not an approved "license free" frequency band anywhere in the world, so you will either need to get a license, or move your operating frequency. 880/915 MHz, 2.45 ghz or 5.9 ghz are possible bands, IF you meet your country's emissions requirements.[/QUOTE]

Yeah i agree, but i'm going to be building a quartz ascillator in the range of 120- MHz then twice trippling and then twice douling the frequency to get it up to 4GHz. I've understand the concept, but like i said the designing the pulse modulated oscillator is what i don't really understand.

by pulse modulating, if you mean simple am on/off keying of the output, that is trivial. At the output, or before the last frequency multiplier, just insert a pin diode spst switch. you do not turn the crystal oscillator on/off, you leave it running 100% of the time.