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How to reduce the I and Q mismatch?

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dinesh agarwal

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there is a amplitude mismatch of about 100mV.

the output is at 2.4 Ghz

how to reduce this amplitude mismatch

what is the reason once the circuit is symetical
 

Re: I and Q mismatch

I/Q Amplitude mismatch appear if:
- Unbalance in the RF splitter used to divide the incoming RF signal equally between the I and Q paths which may introduce gain differences.
- The quadrature 90° phase-splitter used to generate the I and Q Local-Oscillator (LO) signals that drive the I and Q channel mixers may not be exactly 90°. Furthermore, there might be differences in conversion losses between the output ports of the I and Q channel mixers.
- Amplitude mismatch appear also if the filters and ADCs in the I and Q paths are not perfectly matched.
 

Re: I and Q mismatch

Use 1% tolerant components in Both I and Q paths. If you dont have 1% components measure each component and put equal value components in both paths.

regards
GV
 

Re: I and Q mismatch

What kind of effects will result when I and Q are mismatch ?
 

Re: I and Q mismatch

HI,

mainly EVM degradation
 

Re: I and Q mismatch

yashiro32 said:
What kind of effects will result when I and Q are mismatch ?
Click to expand...

If I and Q are mismatch, the image rejection will be reduce.
When amplitude mismatch increase 0.5dB the image rejection will reduce 5~10dB.
 

Re: I and Q mismatch

Hi,

please review the following paper!

David
 

I and Q mismatch

"Unbalance in the RF splitter used to divide the incoming RF signal equally between the I and Q paths"
How does the RF splitter divide I and Q?
 

Re: I and Q mismatch

Hi,
For the RF splitter to split the data into I and Q channels, a clock should be used as one of the inputs to the RF splitter.
bye
Bhanumurthy.
 

Re: I and Q mismatch

Bhanu,
could you pls provide more details (datasheet) of this special RF splitter which splits into I and Q

Regards
GV
 

Re: I and Q mismatch

GVVIN,
The details abt the special RF splitter can be found in the text book"Principles of Communications-Fundamentals through Advanced" by Wayne Tomasi.
bye
Bhanumurthy
 

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