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30 Threads found on edaboard.com: Ads Stability
Thank you BigBoss But it's sure the model is 100% measurement based valid model. But let me add this also that although the device is unconditionally stable over whole frequency range but it's stability factor "mu" is just slightly bigger that 1, like 1.01 and like that. So regarding that these stability factors I mean "mu"
I presume you mean ads with "EM simulation". It offers a combination of analog circuit and EM simulation. ads can be expected to give more precise results in large signal analysis of amplifiers compared to small signal AC analysis of a SPICE tool. But stability results should at least roughly agree. Otherwise one of both analysis is probably (...)
Hello , I am designing an LNA for 481 MHz. Using the transistor BFP420. As a method I am using the complex conjugate matching at output. I have 75 ohms as input and output resistance. 1 - I choose GammaS from the stabil region 2- calculate Gammaout from gammas 3- Find gammaout Conj 4- Check if gammaout and gammaoutconj are in stabil regio
I am trying to design an amplifier using CFY6608 in ads. But I have not used this software before. I have the .s2p file. I have to do stability analysis separately using Data Items option, because s parameters are not available with the built in model I think. How can I perform stabiity analysis using bias network in this case? secondl
I have biased my circuit and i have check the stability. Now my next step is i want to match the 50 Ohm impedance to load impedance here in my case load is Transistor. So i have used the following methodology for my impedance i.e., first i have loaded the s parameters of a transistor then i have given the gain of a transistor which has specified in
Have you had a look at the IXYS stuff, the DEIC515 will get you to 45MHz with plenty of drive current, it may be worth an enquiry. If this is a narrow band application you may be able to tune out some of the gate cap with a suitable inductor, time to fire up ads and have a look at some Smith charts (Watch for stability issues, you really want to
can you help me about choose or change or design the Y-parameter of transistor in the ads?
hi, I want to know the steps involved stabilizing the ldmos based amplifiers. I am using MRFE6S9125NR1. Somehow i was able to get 50 to 70 watts from 925 to 960MHz. But there is some stability issue in 880 to 915 band. ads LSSP Simulation shows that that amplifiers becomes unstable at 33dbm input power. The amplifier is also unstable at s
Why do I get so many smith charts in a single ( 4 circles starting from the centre?) graph while plotting L_stabcircle using smith chart(from the palette) in ads? Which smith circle to choose for interpreting the stable region for output stability circle?
how r u plotting the stability circles ?? thru any tools in ads ?? In general if ur plotting them through equations in data window, U need to edit the equation of that plot which would be for that particular freq in ur case and plot for all values.
Good day, I am designing the front end for a 2m HAM radio. I have selected and bjt and simulated the load stability and found it to be unstable. I have chosen the method of a shunt resistor on the collector. The method requires me to plot conductance circles on the smith chart as close as possible to the plotted load stability circle. Then read o
Obtain your s-parameter by measurements and make compute your K factor for instance in Excel or Matlab... Some VNA's can calculate K-factors.Almost all commercially available simulators such as AWR,ads and the others can calculate K-factor.
hi everybody, i try to design a DRO @ 9.9 GHz in ads. all conditions for stability are satisfied and it oscillates, but the harmonic balance simulation does not look that good to me. i uploaded 2 pics, the schematic and the HB-simulation. what can i do now to improve my output signal? and why does "Vres" at the transistor input look that strange
hi, I am designing a 90 degree hybrid on MMIC in ads. My design is complete with no Transmission lines. I didn't do any design till now with matching networks in ads. I think the next step is replacing all the lines with lamda/2 Trans lines and then after check the input impedance for mismatch and accordingly i should match it to 50ohms.Now af
Why not use other software? Say ads, etc.
Hi, Can ads simulator do a loop stability simulation like spectre stb? Thanks!
Hello, i'm trying to match the input and the output stage of a VHF pre-amplifier using simulation in ads. When i match the output stage everything is ok but when i try to match the input, the output is no longer matched, the gain drops and the stability factor also drops below unity. I guess there is a interrelation between the input and output ma
Hi, I have a schematics file with two different amplifier circuits. Circuit A uses Port 1 and Port 2, circuit B uses Port 3 and Port 4. I'd like to simulate stability for both of them simultaneously, to be able to compare them both. To simulate stability when there is only one circuit which uses Port 1 and Port 2 (as in the following picture)
I used the ads to do the simulation,then it was found that one stage LNA is stable, but the two stage is not stable, I want to know What is the reason?And How can I do with it?Thank u~
Here is an example of an 8.7GHz LNA using GaAs FETs. For your case have to tune (using MWO or ads) Z1 to Z13 transmission lines, to get the best performances in terms of gain, stability, and noise. The bias lines Z7, Z8, Z9, and Z10 are quarter-wave transmission lines. Z11, Z12, Z13, Z14 could be replaced by radial stubs.
You have to use techniques to improve stability of your LNA. To get k>1 at 2 GHz and out of that. It's alway good to improve k outside the working frequency because you get a minor chance to have your LNA oscillating in other frequencies. You can use some techniques to do that: 1)Series feedback: inductor at source (source leads) improve stabil
Thanks RF-OM. The two pictures are in false sequence. The upper one(8V) is the output and lower one(3.6V) is input. second the waveforms are simulated by ads, not measurement. In ads, the voltage swing of any wire can be obtained directly, the current swing can be obtained by insert a I_Probe. how do you mean add resistor at amplifier output?
in ads data display make sure that the smith chart max value is 1 , instaed of autoscale khouly
I did the following simulation to get the source stability circle for the specific transistor (hp_sp_AT-41435_1_19921201). The plot I got for source stability circle is as fig-1 But the plot should look like as fig-2 Actually both of them are same plots. But in my case, the smith chart has been divided into two parts. Th
Hi,all,happy new year! can someone tell me how to use Mu and MuPrime function to determine the stability of an amplifier in ads2003,THANKS!!!
it's a easy work. i think adlab,,mwoffice,ansoft,ads should do it.
Please refer to the pix attached for the simulated circuit. the real part of Zin I got is -52.450@1GHz, -22.039@2GHz. I'm wondering why does this happen. Best Regards.
The definition of stability factor (from ads help) Given a 2 x 2 scattering matrix between the input and measurement ports, this function calculates the stability factor. The Rollett stability factor is given by k = {1- |S11|**2 - |S22|**2 + |S11*S22 - S12*S21| **2} / {2*|S12*S21|} The necessary and sufficient (...)
u can use ads -s parameter-stability circle
2.2 Ghz oscillaotr schematic required also provide necessary files for ads