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254 Threads found on Barkhausen Criterion
Hello all. There are always lots of different definitions for phase margin.... it becomes sometimes quite confusiong. The phase margin problem hapens when you have a feedback system. I believe that the best definition is: 1- A feedback system becomes unstable if the total phase delay of the system is greater than or equal to 360 degrees (Bar
a phase shift oscillator is just basically a type of oscillator. a phase shift oscillator is a feedback oscillator. for a feedback circuit to be an oscillator it must satisfy two conditions (known as the barkhausen criterion). one is that the gain around the closed loop should be unity. and the phase shift around the closed loop should be zero.
Hi all, When I design a ring osc VCO, I run into a problem when I want to simulate the delay cell's gain. I used a pseudo-differential delay element(Sungkyung Park et al.,Elec. Letters May,2001) My question is: how to consider (both in theory and in simulation) the pseudo differential delay element?s gain? According to the barkhausen Cr
Hartley Oscillator - b/c of it's Inductive divider....split inductance. The frequency of oscillator should be: f = 1/(2*pi*√(L*C)) if you NEGLECT the transistor capacitances. Otherwise, you have to replace the transistor with its small signal model and calculate the loop gain. Finally, apply the barkhausen criterion to obtain an
you need to give an initial condition to start the oscillator, is it a 5 stage ring inverter based oscillator or 5 stage differential ring oscillator.For the former you need to just connect the inverters back to back, for the latter you need to set the gain of the differential pairs such that barkhausen criterion is satisfied. amarnath
if three cmos inverters are connected one after the other, will the o/p be stabe or oscillating if the o/p of the last cmos is fed back to the i/p of the 1st cmos... wat if 2 cmos n 1 cmos is connected in the same manner...... i think if 1 n 3 cmos is connected o/p is oscillating,and stable if this correct?..where does barkhausen criter
Hi Prashant, Thanks for the paper. One small question... we know for oscillations to begin other than barkhausen criterion a startup criterion is also required... Is there a relation for the Ring VCO.
An oscillator delivers some kind of energy. Where does it come from ? Answer: Such a passive RC circuit as shown in the link has to be combined with an amplifier in order to work as an oscillator. This passive ladder has the task to produce at a certain frequency a phase shift of 180 deg. Combine it with an inverting amplifier (with the appropriat
What's the matter...wrong forum? /bump OK, I´ll try to give you some hints. In general, you have two alternatives to analyze the CLAPP oscillator: a) The circuit is considered as a two pole oscillator based on the negative resistance principle. In this case, there is no "barkhausen" criterion because this condition is
Thank you ajishgopalr for this video i need more and more explanations Shahabaz, it is not possible to explain here the oscillation principle in detail. *Just some basic rules: The keyword for an oscillatory circuit is "positive feedback". That means, you have to connect an amplification unit (gain A) and a passive
When we design an oscillator, sometimes we design in terms of voltage, then we have to satisfy the barkhausen criterion: gain * feedback = 1. In this condition, feedback is mandatory. But we also use the reflection coefficient to design an oscillator, in which case we have to satisfy the following: Γin * Γs = 1. And usually in this co
The barkhausen criterion requires a loop gain of equal or larger than unity and a phase shift of 360 deg at a certain frequency. In a typical ring oscillator the loop gain always is larger than unity. Each stage has an inherent delay, which can be increased using external capacitors. There is one particular frequency Fo for which this total delay
According to the bode plot of the loop gain, at low frequency, the phase shift is 180 degree, while its gain is well above 1(0dB). It is unstable when we refer to barkhausen criterion. Will the low frequency component oscillate? I have seen a similar question in here but the answers in that thread is really chaotic. So
my question is why did barkhosen criteria specify that 180deg phase shift is very crucial for oscillations to take place??? please elaborate a little..please.. It is not true that barkhausen did "specify 180 deg phase shift" for oscillations. The barkhausen criterion requires a loop gain of unity - which me
Hi, My question may be absurd but can anyone tell me whether we can apply Barkhusen criteria for astable multivibrators? If it is possible,how? No, you can't. The reason is simple: The barkhausen oscillation criterion is based on the loop gain of a circuit with feedback. Any "gain" by definition is a small signal par
hi ,why sability criterion condition,and the spacing is lambda/10,all in FDTD regards
About DVB's RF criterion,who can give some advices?
how is the barkhausen criteria deduced in a ring vco ?
how can barkhausen criteria be related with the simplest ring oscillator based in inverters ?
Hi, Just wonder what is the difference between Abbe and RAyleigh Resolution criterion? Abbe say 0.5 λ/NA while Rayleigh say 0.61 λ/NA So what is the difference or what is the difference in approach? Regards
when i try to simulate some structure in CST MWS at the end of simulate a warning message comes which says "maximum number of pulse widths simulated ,solve stopped please note that steady state energy criterion has not been satisfied" now i get results like S parameters so i am thinking whether i should trust such results when this wa
In current mode DC-DC converter, there is a OTA , that is gm , which connects a resistor with a Cap for compensation. All we know this combination is compensation for system stability. But what is the spec for this OTA ? Does this OTA need to follow AC stability criterion ? That is the phase margin should be large than 45 degree ? what Is it
Hi, iam designing Bandgap ref in 0.35um,3.3v supply,for the opamp in BGR i designed was , ICMR min is 0.65v and max is 3.14v. what is the criterion for ICMR max? (For ICMR min as the input is at around 0.7v,it should be less than 0.7v) Thanks
Hello everyone, I am back with my favorite topic: FDTD. In here I will share a piece of knowledge not easily found. Of course this will care only a handful of people so if you're not interested in FDTD and its biomedical applications then you might as well close this post. I speak of course about the fabled Bioheat Equation (
Does anyone know how to stop the FDTD iterations automatically? Not by setting the maximum time steps. Thanks :cry:
I have designed a dual band antenna that resonates at two frequencies in CST microwave studio. It displays the warning 'maximum pulse widths simulated, solver stopped.steady state criterion not satisfied'. More over when i simulated for freq range 0 to 5 GHz it showed S11 below -10db for both freq and when the freq range was changed to 0 to 3 GHz
Dear all, I want to ask a simple question: Why high order active filter can violate barkhausen's criteria? For instance, if want to design a third-order low pass active filter, there will be three integrators in the loop. In other words, the phase margin is easily less than 0 degree. When we design an active filter, we merely
Why simulators like HFSS and CST use (as a default) absolute convergence criterion not relative? I guess the last method could be more accurate because it for example can make difference between s11(n)=1, s11(n-1)=0.9 and s11(n)=0.2, s11(n-1)=0.1. In the first case relative error is 11% in the second - 200%, but absolute error is constant = 0.1. W
Hi, all, I am studying the MOSFET failure due to Hot-Carrier Injection, and saw this criterion mentioned in all kinds of papers, but none gives the reason. Is the MOSFET just considered as "bad" or "not-working" once reached this 10% reduction in drain current? Or, is this 10% reduction in Id will cause a certain failure rate (like a three s
my structure in CST is too big.(3m*1.6m*1.6* my dimension background material, frequency range is 0.05 to 0.15 GHz , and mesh operation is 15 per wave length per ) because I must to simulate this structure. but it gives me this warning "maximum simulation time reached. solver stopped. please note that steady state energy criterion has not been sa
Hi, I suppose you misunderstood the meaning of the gain margin. The original circuit is stable with a gain margin plus 7.6 dB (because at -180 deg the gain falls below zero dB) - that means you have to increase the gain by 7.6 dB to reach the stability limit. That means: Under these conditions (stability limit) your circuit - after closing
HI guys, Transient simulation. Termination criterion. " To obtain accurate broadband in Frequency domain the Electromagnetic energy in the computational domain needs to be sufficiently decay" "If the energy is not decayed sufficiently the accuracy of the results suffer from the truncation error" I am abit blur. Anyone understand this
Can anyone explain how does the bjt in oscillator automatically adjusts gain so aas to give appropriate output with input as feedback. I think, the most simple and understandable explanation of the Hartley oscillator is as follows: 1.) To fulfill the oscillation criterion (barkhausen) we need a feedback cir
Hi members has anyone ever analyzed on how much Vgs is to be fixed for a MOSFET to obtain maximum "symmetrical" signal swing at the output for the inductive source degeneration LNA using a MOSFET? I am trying to obtain input impedance match and simulatneously maximum signal swing....and am finding it very difficult to interpret the signal swing
I want some online site for prparation of general basic questions of computer networking during the campus written test and interview. if somebody can hel me in this regard 8O If there is some site for good c language objective types again with given criterion. I need this urgently :cry:
Whats the maximum number of meshcells you have simulated in MWS? I wonder what would be the number of maximum meshcells if I use 3 gigs of RAM.
Does anybody know the exact definition of Tangential Signal Sensitivity (TSS) ? Thank you in advance, marco
Dear all, I have read the book - "Design of Analog CMOS Integrated Circuits" on page 499. It said that the LC crossed-coupled oscillator does not latch up because its low frequency gain is very small. Actually, I know that why the gain is low at the low frequency. However, why the low frequency is easier to latch up the circuit (as memory
well phase margin, pole and zero are related to system, and that's why when you want to design "construct some thing which doesn't exist" with given i/p o/p relationship such performance parameters are specified. assume : we have a system "sys" we have time domain response, and frequency response. we want to know at which frequency sys w
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 have a 16 bit DAQ connected to a PC using the USB port, NI LabVIEW driver for this DAQ is available, I want to connect a pressure transducer to this DAQ to measure some pressure value between the lips, what I want to ask is the following: What is the best method to measure the pressure value from the transducer ? , is it to get the maxim
Hi all, For transistor to be in saturation which should be met or both should be met 1. Vds>Vdsat 2. Vds>Vgs-Vth Kindly see the simulation result below of HSPICE . w/l is 10/0.4 Vdd is 1V and VDs is 30mV element 0:m1 region Saturati id -1.2094u ibs 2.957e-20 ibd 5.5275f vgs -550.0
I found that in many papers, the IIP3 was simulated by a two-tone frequencies. But they didn't say how to select the two adjacent frequencies. While in my simulation, if i chose different frequencies, the IIP3 is different according. So what's the criterion? In fact, i'm desinging a wide-band LNA(50~860MHz) now, the spec gives a IIP3 required. S
I can simulate a structure in CST without adaptive pass successfully. But when I run adaptive pass, sometimes, the program will have memory fault error such that I am forced to abort the simulation or the program hangs and I need to re-start the program. Does anyone have any idea why this happens?
I was going through an old exam paper to practice for an upcoming exam and I had a question on a PCM system. I know how a PCM system works but the questions are a little about my head: The ADC has the following spec: Resolution - 10 bits Conversion Rate - 2 micro seconds Input Voltage Range - 0V-5V Power Dissipation - 875mV 1. Calculate
Can any please tell me about basic guide lines for routing of differential pairs in multilayer pcb? Basiacally; consideration for differential impedance about their waveform shapes Seperation criterion between two signals Thanks Abhishek
Hi, Sometimes we use switch-capaictor circuit techniques to design op-amp. Sometimes we don't. Could anyone tell the pros and cons of switch-capacitor circuit? Any input is welcome. Thanks in advance!
The very old barkhausen criteria comes from control systems. It states that if and only if there are poles in the right half plane, the system will oscillate at the frequency where the nonlinearities reduce the loop gain to unity and also the loop phase is a multiple of 360 degrees. This is based on complex number theory. For some reason ever
I am trying to use HFSS for simulating a Sievenpiper type of high impedance surface. I want to obtain the dispersion diagram. 1)how far away I should put the PML from the object (top patch). does it still need lamda/4 requirement as radiation boundary? what is the criterion for PML setting: (a) PML uniform layer thickness (b) minimus radiating di