please give me some suggestions on my design

[yyan71]

I am designing a wireless transmitter device. for the signal up conversion part please see my attached graph.

I think maybe it is hard to deal with the 2.4GHz LO leakage, because the 2400MHz LO frequency is too close to 2400.001MHz RF frequency.

Please advice me how should I design the filter or where can I buy the filter to eliminate the 2400MHz LO frequency, while remain the 2400.001MHz RF signal frequency.


At the same time, I am thinking of applying FM modulation instead of AM. Does anyone know that whether there is a kind of FM modulator can convert 0 to 150Hz signal to IF band say FM tunable in around 200MHz to 1000MHz.

I am a fresh man in this area, I will give thousands of thanks to anyone here who helps...

 

[bigmelon]

Hi, sorry i don't know the answers for wireless transmitter device, but i hope you should already found out the soluion right now.

 

[BigBoss]

Use a VCO that operates 4.8GHz and then divide it by 2 to obtain 2.4GHz..

 

[biff44]

Well, it is an odd way to do it (your schematic).

Do you have access to the analog signal before it AM modulates the 1 KHz carrier?

If so, you could simply use that analog signal to AM modulate a 2.4 GHz VCO directly. (you probably will need a buffer amp between the VCO and the amplitude modulator).

If you really do have to upconvert a 1 KHz AM modulated carrier, the only way to do it with low sidebands would be to first upconvert it to something like 100 MHz, crystal filter it, and then upconvert again with a 2.3 GHz VCO., filter it again.