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1000 Threads found on edaboard.com: Stability Circle
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 (...)
Hi all I am doing an assignment in LNA design. I was stucked up with drawing stability circle. I read the book RF circuit design by chris bowick. In that it was mentioned that to draw the stability circle find the center and radius of the circle with some formulas and to mark the center follow as if to (...)
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?
i ve modified the msg as the previous one was wrong. was confused myself, haven't build a amplifier for many years. anyway, just a tips for you, it's much easier to confirm ur amplifier stability by drawing the source/load termination together with the stability circle (for each frequency), and to make sure that the source/load stay as far (...)
You have an excellent tutorial here: Look under RF & Microwave Theory - stability.
Try to add a small resistor value in source…just to see if you can stabilize. I know the NF will go up, but is an indicator. Usually, if for stability is looking for a high resistor value in source, means that the input match need a different topology.
S11 reflection coefficient of 1.2 is strange. Normally 0
It said that the condition of amplifiers' unconditional stability is K factor not smaller than 1 and delta(S) smaller than 1. But for my simulation, while this condition is satisfied, the load stability circle doesn't lie totally outside of Smith Chart. It means that the load does not satisfy the condition of unconditional (...)
Hello, Recently I have been having some difficulty designing a particular stable CC amplifier. Generally I just work with the amp until it is unconditionally stable and then I just calculate the simulatenous conjugate match or determine the load that will provide a particular gain from power gain circles. I have been trying to design a CC amp fr
u can use ads -s parameter-stability circle
Why you do not make an amplifier in these ranges, add positive feedbacks to move in stability circle of smith chart and make the oscillator? I know this way you can make the oscillator which will have frequency stability pretty nice.
Hi there! I need to design an amplifier using ATF-36163 transistor. I also have to use Ansoft Design (I have not really get the hand of using this yet). The amplifier is to operate at 5Ghz (that's the only requirement in terms of variables). I already have the S parameters in hand. However, I am quite lost on how to start. I have looked at t
Hi all, I am designing a LNA. In ADS I get the stability factor 1.004 and the stability measurement 0.391 but the stability circles (both source and load) include the whole Smith Chart! The stability factor and measurement say that LNA is stable, but the stability (...)
To follow up: As noted K>1 says stability but give no hint at how far outside the smith chart the stability circles are. Similarly if you get K<1 it doesn't give you much insight as to what to do, or where to do it. On the other hand Mu and Muprime have direct relation and give great insight. Mu is the distance from the center of (...)
Hello, You said you designed means simulated or fabricated a prototype!!! The S11 can't be positive their may be some problem with the device model parameter or file... Yes, it is unstable (oscillations), plot the K or B1 stability factor plots or stability circle measurements on smith chart.... See more here
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 (...)
Hello Friends I need an emergency help. I am studying with amplifier design. I have a TI calculator with that I need to calculate lot of equations, those are below. 1. Reflection co-efficient 2. Impedance 3. Gain 4. Radius of stability circle 5. center of stability circle 6. K 7. Delta so on etc I (...)
if you don't know the ROC, it is generally impossible to say about stability. a transfer function may correspond to some stable and/or unstable functions.
why it is necessary that region of convergence of any stable system must include unit circle in z plane?
Do any stability test. Take reference from any control system book.
I want to ask, are there any other cases than that: Output stability: 1) |S11|<1 2) |S11|>1 Input stability: 1) |S22|<1 2) |S22|<1, but Rin>|Cin| 3) |S22|>1 does this inversion rule "but Rin>|Cin| [stable inside circl
Smith Charting with stability and Noise circles It charts stability and noise circles.
If the PLL sinthesyzer is single loop type then the PPM stability will not change. If it consists more loops, then you should calculate it by simple mathematics.
Hi all,I wonder if somebody would like to help me with an optimization problem in Matematica. I have the so called S-parameters (S11,S12,S21,S22) of a transistor circuit and are complex valued. I want to maximize the trancducer powergain function Gt= *|S21|^2* Constraints: R_in= S11
8) To check the feedback loop stability there are specialised Feedback analysers. There is a e book in MCU filemaan Home / eBookNew / Switch Mode Power Supply Handbood
Use an ordinary op amp instead of the comparator. This will make the system loop gain more linear. Then you can brute force the stability by putting a capacitor across the op amp inverting input to output.
stability means lack of self oscillation. Ruggedness means no permanent damage to the transistor.
hi ,why sability criterion condition,and the spacing is lambda/10,all in FDTD regards stability condition where? in what? for what? please add more information.
Hi, the time step should to affect the results (only the calculation time) If you reduce the PBA fill limit to let say 70% (default 99%) the PBA cell is only used if the cell if filled with less the 70% by metal. If the cell is filled by more then 70% by metal, the entire cell is considered to be metal. Sometimes the port setup can influence
As we know PA has noise circle and gain circle, but in your practical experience, is it impractical to consider it and just use the try and error method? Best regards.
stability check using transient analysis is a good way to verify the open loop AC analysis. Insert a step at the input of the loop and watch how the loop settles, you will probably see a damped sinusoidal response. I've done this in SPICE many times for verification. But 10 deg phase margin is very low. Aim for 60 deg phase margin and 6 dB am
hi all,i add resistor at drain of ATF36077 to make k>1 in all band(8-12 GHZ) but the stability still < 1 .any method to make stabilty >1 regards
hi all.what differ between the stability factor and stability factor measurment at ADS2003 (stability factor >1 and measured one less one) what i talk care ? regards
I know how to work on phase portrait and to find the stability of the system can any one tell me how we can apply energy methods to determine the stability of the system.
try v5.1 beta 2. I have encountered less stability problem with this version. Element7k
Who can help me with phase stability in a solid state transmitter? How is it defined? What is it? How can I measure it? Where is possible to find some references? Thank's in advance.
Hello, I have some question about the stability of the system. The basic criterion about the stability of the system is whether it has the poles in right half-plane. Assume that the system has the pole P0(Unit: radians per second) in right half-plane. I think the step response may oscillate with the frequency at P0/(2*pi). But if the input signal
hi,i design with stability factor>1 but measures one (.9-1) is there is oscillation pls reply regards
The most advanced, and the most difficult to do is the Allan Variance. Too long to explain here. That's the good way. :) Here's an explanation straight from the horse's mouth:
I think GBWcmstability when you make GBWcm>GBWdm
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 conditions for (...)
I need the papers about loop stability in low dropout regulators thank's
If you want to improve temperature stability for coaxial filters, you can use very good and expensive material - invar.
Hi all, does anyone have some experience with ADI solver for FDTD? What's about stability in time domain? To how low frequencies is it possible to arrive? thanks and best: Ricy
Best way to measure stability to put a step load at the output and do a tran analysis & see output waveform for stability .Try to tweak ESR a little .
Are there methods that can be used to improve the stability and convergence rate of the adaptive IIR filtering? Thanks.
I want to know how many the compensation technology for stability for power IC. For example, miller compensation and slope compensation and so on. Is there any other compensation technology for stability?
HI, In ADS, the GP circle is for load impedence matching network, how to map it into the source side? SO that we can combine it with the Noise Figure circle. Thanks a lot. Best Regards, Tony
Hi, For the amplifier design in ADS, how to plot constant VSWR circle on Gamma-S and Gamma-out plane? Here, VSWRin for input port, and VSWRout for output port. Thanks a lot. Best Regards, Tony Tao
it is easy to check the stability of the power amplifier,follow the following steps: 1) link the signal source and the power amplifier and the attenuator with the spectrum analyzer. 2) set the power amplifier analyzer full span 3) then turn on your power amplifier and let the signal source shut down(no rf signal output) 4)observe the