qpsk upconverter

Thread Starter

ranaiftikhar

Joined Nov 1, 2016
42
hi

i am new in communication circuits. please apologies for any inconvenience.

i am searching for passive QPSK mixer (Upconverter). i found following details in one thesis:

upload_2017-4-12_21-37-45.png
ref: https://open.library.ubc.ca/cIRcle/collections/ubctheses/24/items/1.0065575

can i use RF/IF interchangeably for down conversion and up conversion?
or please refer me some good link for upconverters.

thanks
 

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Thread Starter

ranaiftikhar

Joined Nov 1, 2016
42
hi Sitara

thanks for your response.

i found a lot of data (upconverter) but all with active mixer (like Gilbert cell). can you guide me about any major drawback that passive up-converter is least used in up-conversion?
 

Sitara

Joined May 2, 2014
57
hi Sitara

thanks for your response.

i found a lot of data (upconverter) but all with active mixer (like Gilbert cell). can you guide me about any major drawback that passive up-converter is least used in up-conversion?
See page 29 of the following:
http://ece.ut.ac.ir/Classpages/F88/ECE606/files/mixer.pdf

The main disadvantages are (a) Insertion loss (b) Intermodulation distortion (c) local oscillator feed-through. These are the same reasons why Gilbert cells have overtaken passive mixers in most RF mixing applications.
 
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