upconverter in transmitter

[khouly]

gsm upconverter

i am design an up conversion mixer in TX , but the IF power is saturating the mixer in my design , when i use 0 dbm as the IF input , i found that the output power is about -6 dbm

but when i just made the input power -30 dbm IF , i found the upcomverter singal have about -18 dbm , this means i have about 12 db gain

i need to make the mixer work in 0 dbm , any recommendations

khouly

 

[mirabella2]

You use what type of the mixers?
You use what frequencies?
Can use some mixers?
To divide a signal on an input and to summarize on an output?

 

[khouly]

the frequency of the output is about 7.3 Ghz ,
the IF is 2 GHz , the LO is 5.3 GHz

khouly

 

[fanshuo]

you have voltage gain more than 3dB, so you must use gilbert cell.
Assume you use CMOS transistor
In case the IF signal is so large that makes the input transistor works in linear region instead of in saturation region, I think you should decrease the load resistor and increase the transconductance gm.

regards

 

[khouly]

i am designing a microwave one , based on discreete HEMT

khouly

 

[Lance_RFdude.com]

have you tried the resistive fet mixer yet? I've seen compression points at least in this ballpark at this frequency range using the NE32/4210 devices.

Lance

 

[radiohead]

Why don't you use a Hittite mixer? hmc219ms8.pdf has a typical input referred 1 dB compression point of 10 dBm. I would certainly advise a passive mixer for better linearity.

 

[khouly]

lance
i am working in the resistive mixer now , but ididn't get this compresion point

radiohead
my supervisor want it to be designed by me , not a of the shelf mixer

khouly

 

[benever]

I am doing a quadrature mixer too, need your help!



thanks!

 

[khouly]

what do u need , i have finshed the mixer design , we can discuss the design

khouly

 

[benever]

i am going to design a quadrature up conversion mixer in the Tx,


the LO is 2G and the IF is 5M


need the output is 2.005G


help me !

 

[studbdude]

i need to design up converter whose IF 70 mhz and for c band i m dealing in earth station design will u people help me in that query

 

[angu]

Downconverter using coupler and diodes

i need to design a dual band mixer (GSM - 900 MHz and 1800MHz). i used a dual band hybrid coupler in ADS, converted this layout in to schematic and added diodes.My desired IF is 500MHz.I designed a filter for tht frequency also.Now my problem is i dont know how to give inputs(RF and LO) and to which ports of Hybrid coupler in ADS.dont know how to use tht sweep plan. can anybody suggest me the solutions....

 

[khouly]

try to use parameter sweep , it is much easier than sweep plan

khouly

 

[ttkane]

Maybe you can using DESIGN GUIDES,that have some sample can be pratices.
I'd ever using transistor design UP-converter.
maybe you can using BFT25 transistor, good luck