How to improve I/Q mismatch ?

[ccw27]

Can anyone provide me references on how to improve I/Q mismatch?

Thanks

 

[hrkhari]

improve iq mismatch

In RF design, commonly phase shifting network contribute primarily to I/Q mismatch, using octet phase generation would help in compensenting it.

Rgds

 

[ccw27]

phase amplitude mismatch

hi hrkhari, can you talk more about octet phase generation or provide reference?
Also I know you can also perform digital pre-distortion, is there any other method other than digital?

Thanks

 

[qiaoxp]

layout i/q mismatch

1/4 λ microtrip line can produce 90-degree phase shift

 

[nxing]

i/q mismatch

have you ever try polyphase filter?

 

[springf2000]

iq mismatch polyphase

y can use the digital technology to overcome the analoge IQ mismatch,

but if y tell me the concrete condition ,i can recommend some device with good IQ match

 

[multanova51]

iq view mismatch filter

Hi there
There are 2 types of mismatch:
-amplitude
-phase

If you maintained nice electrical length between I and Q inputs then the main thing to do is adjust amplitude of one channel in respect to the other.
If you need more compensation, the phase needs to be adjusted. In a measuring setup it is easy.... just fool around with some different lenghts of coax in one channel. In a real application this is not possible.
A sort of calibration routine might help to adjust amplitude & phase. This calls for software.

rgds

Mike

 

[spweda]

polyphase filter i/q mismatch

The requirement for I/Q mismatch depends on the modulation. The BPSK/QPSK could tolerate more phase/amplitude mismatch than 8 PSK or 16 QAM. Based on your system, I/Q mismatch may be compensated at the baseband using DSP.

 

[qyinn]

i/q mismatch polyphase

Hello,

There is this doc at Tropian on the error sources in an IQ modulator:
**broken link removed**

It can indicate which are the most important error terms that need to be corrected.

 

[DonJ]

Re: I/Q mismatch

Hi,

Improving I/Q balance- Some issues to consider:
- Good quadrature phase balance (polyphase filter, divide-by-2 or 4)
- Good amplitude balance (limiting in some cases)
- Symmetry in layout critical (use dummies if necessary)
- Calibration if very high performance required by your system

All the best