Help me select a IF mixer for project that measures high frequency range

hi all, i want to ask some question about mixer, ihave project to measurement high frequency (RF) range 100 Mhz - 500 Mhz, i have plan to using mixer and get IF freq in 20 Mhz, the osc using pll, i want ask you :

1. what mixer suitable for my project, the IF freq can change.
2. if i used mixer, is the frequency and amplitude in RF that i would measure will change?.
3. i plan to draw the RF freq in PC,

give me some advices,

thanks

u can use , single balanced mixer , or a duoble balanced one

i don't understand ur other questions

khouly

1.) You can use dual gate fet to built an active mixer, the isolation is alright. An appnote is attached for your reference.


2a.) IF frequency of the mixer suppose to be unchanged. Therefore, you should change the VCO frequency ( normally control by PLL ) in order to keep IF coustant. This is what normally do for rf modules.

b.) Change VCO amplitude or rf input signal amplitude will definitly change the amplitude of IF output signal. Normally the amplitude of VCO will set to around 0dBm depending on the saturation point.

3.) Do you mean you will connect the mixer IF out to PC ? I don't thik it works this this way.

thanks for your suggestion, for no 3, i mean i want to draw the the IF frequency on computer.can you give me some link to learn more, ...., next time i attached with diagram block...
thanks

I found problem on upload the mixer appnote. Please get from the following link

www.cel.com/eng/eng_notes.asp


Appnote no. AN1020

you can use some bjt do it, the mix is very easy .