Any reading material about Polyphase Filter?

[cmosbjt]

Basic concept and its applications?

Thanks

 

[VSWR]

**broken link removed** CircuitLab/CirLab_Proj4_PPF35.pdf

(copy the WHOLE string to your browser and replace ** by tt)

You also get a long list from Google Search using the following keywords:

Polyphase Filter

 

[cmosbjt]

h**p://larc.ee.nthu.edu.tw/~jcbor/ CircuitLab/CirLab_Proj4_PPF35.pdf

(copy the WHOLE string to your browser and replace ** by tt)

You also get a long list from Google Search using the following keywords:

Polyphase Filter

Thanks a lot.

 

[cmosbjt]

atually, it's hard to find text books that have thorough theoratical/mathematical analysis of image rejection by Mixer + Polyphase filter

 

[DonJ]

atually, it's hard to find text books that have thorough theoratical/mathematical analysis of image rejection by Mixer + Polyphase filter

Hi

There are some really good IEEE papers about this subject.

A. T. B.

 

[cmosbjt]

I summary the theoratical analysis of image rejection by mixer and 1st order polyphase RC filter here. Any mistake, please add your comment.

Attachment delected, please refer to the latest version below.

 

[dhlee]

I summary the theoratical analysis of image rejection by mixer and 1st order polyphase RC filter here. Any mistake, please add your comment.

In your analysis, S is not a real signal. It is a complex signal having only positive frequency.

What is the purpose using the polyphase filter? An ideal quadrature mixer have no image response. Do you intend to secure channel selection in complex domain?

BR

 

[cmosbjt]

In your analysis, S is not a real signal. It is a complex signal having only positive frequency.

you can replace the complex signal with real signal as sin or cos, the result is the same.

What is the purpose using the polyphase filter? An ideal quadrature mixer have no image response. Do you intend to secure channel selection in complex domain?

What do you mean "An ideal quadrature mixer have no image response"?

 

[dhlee]

In your analysis, S is not a real signal. It is a complex signal having only positive frequency.

you can replace the complex signal with real signal as sin or cos, the result is the same.

What is the purpose using the polyphase filter? An ideal quadrature mixer have no image response. Do you intend to secure channel selection in complex domain?

What do you mean "An ideal quadrature mixer have no image response"?

In my thought, the S of your analysis represent the real signal that have positive and negative frequency. If it is right, as you said, S should be replaced by sin or cos signal.

As you said, the output frequency spectrum in complex domain, whether S is a real signal or not, may be same, because the Quadrature mixer is a single-sideband mixer.

At the output of mixer, you can discriminate between IF-signal and image signal by frequency difference (eg. positive and negative). The output spectrum is just frequecy-shifted version of S, so I think that there's no need to analyse the mixer operation.

BR.

 

[cmosbjt]

In my thought, the S of your analysis represent the real signal that have positive and negative frequency. If it is right, as you said, S should be replaced by sin or cos signal.

As you said, the output frequency spectrum in complex domain, whether S is a real signal or not, may be same, because the Quadrature mixer is a single-sideband mixer.

At the output of mixer, you can discriminate between IF-signal and image signal by frequency difference (eg. positive and negative). The output spectrum is just frequecy-shifted version of S, so I think that there's no need to analyse the mixer operation.

S=A×exp(jωt+φ) can be used to represent a true signal no mater it is sin or cos or complex. It is a generalization expression. If you have time, you can replace it with sin or cos, you will get the same result.

"At the output of mixer, you can discriminate between IF-signal and image signal by frequency difference (eg. positive and negative). " Yes, you are correct. But you can not tell difference between cos(ωt) and cos(-ωt), right? Without the PPF, how can you reject the image of negtive frequency?

Please refer to the attached paper, you can get the idea.

 

[dhlee]

Dear cmosbjt

I feel a great interest in your analysis about the PPF.

I thank you to give me a chance to read your elaborate analysis.

I wish that my some commments are helpful to you.

S=A×exp(jωt+φ) can be used to represent a true signal no mater it is sin or cos or complex. It is a generalization expression.

I think that S=A×exp(jωt+φ) is not a generalized expression to represent a true signal. It can exist in only complex domain.

If you have time, you can replace it with sin or cos, you will get the same result. .

Yes, you are right. The results are same, but the reason is due to the single-sideband mixer.

Let S_complex=A×exp(jωt+φ) and S_real=A×exp(jωt+φ)+A*×exp(-jωt+φ)

S_complex * S_LO(=A_LO×exp(-jωt+φ)) = AxA_LO
S_real * S_LO = AxA_LO + A*xA_LOxexp(-jwt+φ)

At mixer output, the baseband signals are same.

"At the output of mixer, you can discriminate between IF-signal and image signal by frequency difference (eg. positive and negative). " Yes, you are correct. But you can not tell difference between cos(ωt) and cos(-ωt), right? Without the PPF, how can you reject the image of negtive frequency?

You mean the difference between exp(jwt) and exp(-jwt)?? cos(wt) and cos(-wt) are exactly same signals. I don't deny the need of PPF to reject the negative frequency. The PPF or complex filter to eliminate the potential image signal is definitely needed in low-if receiver. But, firstly, in your analysis the negative frequency at mixer output is not a image signal of mixer, It's just potential image signal in baseband process(BB stage or final direct conversion using double quadrature mixer) . The image signal of mixer can't be eliminated at the output. Secondly, I wonder why do you analysed the mixer operation. In mixer output, you can get the only frequency-shifted version of the input signal. You can express the PPF input signal by inspection not by the difficult analysis of the mixer operation.

Best Regards

 

[cmosbjt]

Hi dhlee,

Thanks for your comment. I agree with you and I revise the analysis in the attached file.

 

[pool_77]

nice
h t t p://home.planet.nl/~niess153/Polyphase_networks.htm

 

[aryajur]

This topic is covered somewhat in the book "CMOS Wireless Transceiver Design" by Jan Crols. The paper is a good one.

 

[borodenkov]

Have a look at these papers:

Abidi group:
Behbahani et al, "CMOS Mixers and Polyphase Filters for Large Image Rejection", JSSC, June 2001

Allstot's group:
Fang et al, "An Image-Rejection Down-Converter for Low-IF Receivers", IEEE Trans. on Microwave Theory and Techniques, Feb 2005

 

[yolande_yj]

This topic is covered somewhat in the book "CMOS Wireless Transceiver Design" by Jan Crols. The paper is a good one.

Hi Arjajur, can you share this book? Thanks.

 

[aryajur]

Unfortunately I don't have an ebook copy of this book. I was looking for the book, but could not find the ebook copy, sorry!

 

[eejli]

hi,Borodenkov

Do you think abidi's paper a good guide? I always find his paper full of math and hard to understand. Does his paper really convey some important insights and understanding rather than make other people more confused?

Thanks.