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The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl Design >> RF Design >> help needed to design a class F power amplifier https://designers-guide.org/forum/YaBB.pl?num=1193043253 Message started by akrathi on Oct 22nd, 2007, 1:54am |
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Title: help needed to design a class F power amplifier Post by akrathi on Oct 22nd, 2007, 1:54am Hello to all, I am very new to RF designing and I am a student... I am designing a class F PA for LINC TX(outphasing transmitter), I am using cadence spectra tool to design PA and I have couple of questions... 1. how to simulate the envelope simulation using spectra... since my PA is for EDGE communication standard so I have to respect the Mask, so I have to see whether my PA output spectrum is meeting the EDGE mask or not, in cadence how to generate the I/Q baseband signal and do rest of the signal processing to feed input singal into my PA. I suppose this is possible through matlab+Virtuoso AMS+simulink coupler, but I don't have license for AMS tool. is there any other way to generate the baseband signal? I have ADS tool (since I don't have STM models files for ADS so I can't use ADS) lets say I will generate the baseband signal from ADS and save it into .dat file, so does it is possible i can use this .dat file into cadence to simulate envelope simulation. 2. is there any other way to check my PA linearity? since my PA is switched kind of amp(not linear like A, B, AB and C) so I can't sweep my input signal power (which is fixed 1.2V square pulse coming from divider ckt after VCO) and also this is a large signal, but PSS and PSS + PAC simulation is only for small signal... looking into these fact dose IIP3 or ACPR are making any sense to switch PA amplifier (these spec is for linear PA I suppose), so how do I check my output mask requirement. can I do two tone test using pss (I can apply two tone spaced by 200kHz channel small signal into my vco and check the IP3 IP5 etc... using pss simulation and if results are good I can assume my PA will meet the mask... 3. what is the diff between ip3, ip5.. and ACPR... 4. how do I check the stability of my switched PA if my input is not small signal and I can't sweep it (input is a pulse of 1.2V peak). I have some more question but since this mail is too long so I will ask in different topic... thanks in advance for positive replay... Amit |
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Title: Re: help needed to design a class F power amplifie Post by pancho_hideboo on Oct 22nd, 2007, 2:29am Hi. Quote:
I don't think license for AMS tool is mandatory. Just use vpwlf or ppwlf source with generated I/Q baseband signal files. You can create I/Q baseband signal using various tools such as MATLAB, ADS_Ptolemy, SystemVue, SPW, etc. Quote:
What do you mean by "STM model files" ? Quote:
What is ".dat" file ? Quote:
I don't know your ".dat" file, but you can use ADS results file in Cadence Spectre using vpwlf or ppwlf source. Quote:
Class F is nonlinear amplifier. So you have to evaluate ACPR and Power_Efficiency applying actual modulated signal. Quote:
I can't undestand the above question. Express in detail. Quote:
You can do using pstb analysis(Periodic STB Analysis) in Cadence Spectre. |
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Title: Re: help needed to design a class F power amplifie Post by akrathi on Oct 22nd, 2007, 3:25am Thanks for your replay... I have generated the baseband signal from ADS EDGE signal source and save the data(mag and phase information) into a file, the extension of this file is <finename>.dat (data file generally use this extension), does cadence understand this format? suppose if I will give this file to vpwlf signal source does it understand this format? STM model files means ST Microelectronics Model files. what I mean is: does IP3 and ACPR are the same definition or will give you same information? for nonlinear amplifier does IP3 make any sense? Thanks Amit |
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Title: Re: help needed to design a class F power amplifie Post by pancho_hideboo on Oct 22nd, 2007, 3:48am Hi. Nobody can understand your questions unless you describe correct tool's name, situation and condition in detail. Quote:
You seem to use "SDFWrite" component in Ptolemy Domain of Agilent ADS. Right ? This is binary data for Vector Signal Analyzer such as Agilent VSA89600 or 89400. Quote:
Spectre can't read SDF file. As far as I know, there is no simulation tools which can read SDF except for ADS Ptolemy. Even in ADS Ptolemy, occasionally we can't read SDF. Currently standard format might be MAT File(MATLAB Binary File) even in VSA89600. Use "Sinks/TimedDataWrite" in ADS Ptolemy for I and Q signal, then save each file as Isig.tim and Qsig.tim. After easy modification of these files, you can use them in Spectre. Quote:
What is this ? Transistor model ? Quote:
Of course, they are different. Quote:
You can relate them to some extent. |
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Title: Re: help needed to design a class F power amplifie Post by akrathi on Oct 22nd, 2007, 5:47am Hi, Thanks for your valuable feedback and comment. yes you are correct I am using "SDFWrite" component in Ptolemy Domain of Agilent ADS. I got the "Sinks/TimedDataWrite" in ADS Ptolemy, but as you said after easy modification of these files, you can use them in Spectre. can you please let me know what are the modification required to use them in spectra. STM model files means : its a CMOS090 90nm design kit given by ST Microelectronics. Thanks Amit |
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Title: Re: help needed to design a class F power amplifie Post by pancho_hideboo on Oct 22nd, 2007, 8:29am Hi. Since your question is usage of tools, so you should read both ADS and Spectre manuals deliberately. If you can't find necessary information even though you read manuals, you should contact with technical support of Agilent and Cadence. Quote:
Tool name is Spectre not spectra. Do you know usage of vpwlf or ppwlf of analoglib in Cadence ADE ? Also read ADS manual about "tim" format data. Maybe no modification is needed since vplwf and ppwlf ignore lines which is not numeric if my memory is correct. Quote:
Do you have RFDE or Dynamic_Link license from Agilent ? If you have either of them, you can do ADS simulation of composer schematic using PDK for Cadence directly. And if you have WTB(Wireless Test Bench) in RFDE, you can use Ptolemy signal directly in composer schematic. |
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Title: Re: help needed to design a class F power amplifie Post by akrathi on Oct 23rd, 2007, 3:52am Hi, i don't have license for RFDE or Dynamic_Link so i can't used cadence using ADS. but meanwhile I am able to simulate tran simulation using vpwlf signal source, i have save the two phase information Θ+Φ and Θ-Φ into .tim file from my ADS LINC test bench, in cadence i have written verilogA script to generate PM signal using these two phase and feeding it to my PA. now the problem is i have to run the envelope simulation in this test-bench, although i got the example from cadence source-link database, where they have used the envelope simulation for cdma signal source. i have also done the same thing i took two pwl signal port and in pwl file name field i have given the path of I/Q .tim signal files and in frequency name 1 field i have given the my carrier freq name(RF_Freq, value of this variable i have set 1.8GHz in ADE window), the problem is in envelope analysis window i have to give the clock name field and when i am saying chose from schematic (by clicking on select clock name) it is giving error like "no source frequency name found" and my envlp simulation is not proceeding. does any one has face this problem before or i am doing some this wrong? although i can plot the PSD from output voltage waveform from my tran simulation using calculator function but it is not so accurate ( bkz it will do the dft analysis) does anyone try this, if, any comment are welcome. i tried also but it is plotting output in uV at carrier freq i don't know how to interpret it? |
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