Complex signal mismatch in high power amplifier

[hk]

Hi,I got some problems here. For SSB, after summation of real I and imaginary Q part using add block,these
error occur in High power amplifier:

1)Complex signal mismatch. Output port 1 of 'Memoryless
Nonlinearity/Merge' is a signal of numeric type complex. However, it
is driving a signal of numeric type real.

2)Complex signal mismatch. Input port 1 of 'Memoryless
Nonlinearity/Out1' expects a signal of numeric type real. However, it
is driven by a signal of numeric type complex.

This is the error that i get from simulink simulation.Anyone knows
how to solve this problem? What HPA block should i choose for nonlinearities,IIP2 and IIP3 in simulink?Am/PM effects of amplifier is not included.

Thanks for any advice.

 

[Harmasha]

complex signal mismatch simulink

Hi,
It was long I worked with it.
But remember such an error.
Try to have magnitude and phase of teh complex value that it is stating to be the output of Adder or the Mixers(These are memoryless mergers).
Its a+ib form. You need to have magnitude ( squareroot [(a^2) + (b^2)] )
and phase (tan -1 (b/a) ) separately in two blocks. This should work.

 

[hk]

local oscillator in simulink

Hi,really thanks a lot for your reply.May i know how to change and where to change the complex value to magnitude and phase value?is it i need to u 'complex to magnitude and angle' block at the output of 'Add' block?But there is only one input for HPA...

Or is it i need to use a 'Abs' block to get y=|u|?But if i use this,how about the phase?

I am implementing RFID model in simulink.May i know whether u try on it before?
Thanks for reply!

 

[Harmasha]

local oscillator+simulink

Hi,
You should be right. Taking the magnnitude to HPA is ok. For phase you can have a separate calculation for the output phase component (I dont know how to implement the tan-1(b/a) part. You should be having a math block for this) . Then you shift the phase of the output magnitude. This should give you a signal that can be view by a scope at output end.
( Hope I cleared you now. Sorry I dont have matlab right now. )
Any body help us.

 

[hk]

shifting a signal in simulink

Hi Harmasha,thanks a lot for your help.I have tried on putting a 'Abs' block to get y=|u| after the 'Sum' block but still getting the same error-->Complex signal mismatch...
and i stil not very sure on the phase part and how to shift the phase of the output magnitude coz i cant find something similar in simulink block...
Anyone knows how to solve this error?
Thanks for reply!

 

[Harmasha]

merge simulink help

Hi hk,
If the error is occuring at nonlinear merger. It is adder or mixer.
You can note this in my prevoius message also.
Now that the adder is adding the real and imaginary parts. So the input of adder should be of same type. This is one point for you to get error.
This is a possibility.
Secondly, the LO is just slpit and given to real and imaginary parts to the mixers.
Thirdly the imaginary part of the input is combined with local oscillator's output in mixer1.
Try to check these areas. Also the error says about "Memoryless nonlinearity/merge" and "Memoryless nonlinearity/out1" I dont know what it is refering to. Try to rename the mixer and local oscillator output separately and find out what they are refering to. Sorry buddy. I am left out with this trial and error only.

 

[hk]

how to view a complex signal in simulink

Hi Harmasha, thanks again for your reply.The memoryless nonlinearity is actually the simulink block that i used for high power amplifier and the errors are occured in this HPA block.
I don't know is it correct for me to use this memoryless nonlinearity block to represent the HPA with onlinearities,IIP2 and IIP3 ,Am/PM effects of amplifier is not included?
Can anyone help me on this?Thanks for replies.