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  1. #1
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    How to reduce the I and Q mismatch?

    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

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    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.



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    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



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    Re: I and Q mismatch

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



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    Re: I and Q mismatch

    HI,

    mainly EVM degradation



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    Re: I and Q mismatch

    Quote Originally Posted by yashiro32
    What kind of effects will result when I and Q are mismatch ?
    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.



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    Re: I and Q mismatch

    Hi,

    please review the following paper!

    David



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    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?



  9. #9
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    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.



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    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



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  11. #11
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    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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