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91 Threads found on Noise Match
Hi, I'm performing a noise analysis in LTspice IV. Unfortunatly te function LTspice2Matlab, which is available at just supports transient and AC analysis. So I have to export my resulting noise density voltage via File -> Export. The exported file format is a txt document. After importing the values from
Hello guys, I am designing an LNA and would like to match it for a nearly optimum noise condition. I´m running in trouble trying to design the input matching network, which should convert a 50 ohm source to my desired source impedance (let´s say 10 + j*10 Ohms). So far the matching tools that I´ve been using (...)
First of all, your attachment didn't make through. There are exactly 4,193 reasons why this isn't working; a few of them are: Your baudrates don't match Your parity doesn't match noise You don't have your handshaking signals driven (or connected) (they supply power for the device) Your cable is incorrect Your software is incorrect (not (...)
Most of the high-linearity VGAs use an integrated step attenuator in front of a fixed gain amplifier, as for example LMH6521 from TI: Advantage using a step attenuator in front of the fixed gain amplifier is not only to keep good linearity, but also to improve input/output match, and the gain flatnes
Rather then a function generator, a sine wave oscillator 20 - 20kHZ with really low distortion, say 10 times lower then the distortion that you would expect to get from your products. And to match it a noise and distortion measuring set or a wave analyser (audio form of a spectrum analyser). With a suitable load, you can then set up the rated p
Your initial assumption is wrong. LNA respectively FET input impedance is never purely capacitive. You possibly want to review s-parameters of a real LNA. LNAs are typically used for applications related to their name Low noise Amplifier. If low noise is an objective, impedance matching matters.
johnjoe Sir, Yes, exactly what you said that is correct. I need to calculate the noise FIGURE numerically with the attached formula that should match with the simulated noise FIGURE = 0.543 dB(it is shown in the posting # 1) and which value we have to take for GAMMA S(Γs). Please can you help me sir.[/QU
Can we use conjugate matching at the input for mimimum noise matching ????, Can anybody explain the logic behind not using conjugate matching for minimum noise matching I think you are getting it all wrong here. Low noise devices are characterized by Γopt provided (...)
If the amplifiers became more sensitive to the pickup noise, consider a better screening and input low´-pass filtering.
The junction of R4 and R5 will produce much less noise if it has a filtering capacitor to ground. You do not need a buffer at the input of the simple filter. This circuit uses signal voltage, not signal power. If you match impedances then the signal level drops to half, which will double the noise level.
It is very common. A good example are GaAs FET amplifiers. The gate of the FET may have a S11 of >.9 making it very difficult to get a good match at a single frequency due to component Qs and stability issues. This task becomes impossible over a broad frequency range. Also the optimal noise figure match does not occur with a S11=0 but (...)
Hello all, I am designing a Common source Cascode low noise amplifier. How do we match the circuit at the output to 50 ohms ? As I understand , we use an inductive load to get rid of parasitic capacitance of the transistor. So, we are only left with the intrinsic resistance of the transistor. We can not use the matching network to (...)
Hi all, I have question about the receiver noise figure. If I have a rx antenna with 6dBi gain, and the duplexer with 2dB loss cascaded after the antenna. Then what's the output noise power at antenna output and duplexer output, suppose that all interface are conjugate match. If I need to caculate the receiver the noise (...)
Hello Edaboard, Please check if my explanation for PLL is right, if any mistakes please correct it. PLL is a device which makes use of negative feedback so as to match the frequency and phase of a input signal avoiding noise and jitter in it to the ouput signal. So the output signal will have the
The idea is to estimate the spectral magnitude of noise using noise match filter, and making use of the fact that power spectra of additive independent signals are also additive and that this property is approximately true for short-time estimates as well. Hence, in the case of stationary noise, it suffices to subtract the (...)
Hello, Currently I'm working on the LDO reg. PSpice macromodel but I have some concerns about the output noise modelling. After studying some papers on Op-Amp macromodels I was able to obtain fairly good match between the Output Voltage noise Density Measurements and Simulations in 10Hz-1MHz bandwidth. (The noise source (...)
... Some say series is good as it will match the models well I think you picked the right point. But if you don't need high accuracy results from the analysis, a single long transistor will work quite well -- if it's allowed by your PDK simulation models. There should be no difference in noise injection for
Use a timer set to compare match that toggles the output // Timer/Counter 1 initialization // Clock source: System Clock // Clock value: 16000,000 kHz // Mode: CTC top=OCR1A // OC1A output: Toggle // OC1B output: Discon. // noise Canceler: Off // Input Capture on Falling Edge // Timer 1 Overflow Interrupt: Off // Input Capture Interrupt: Off
With Monte Carlo you might have to run 30-100 simulations before you got a good estimate of the standard deviation (SD) due to random mismatch. On the other hand, DC match is a sensitivity analysis that is much like a noise analysis. It will give you the SD in a single simulation, making it very useful for large circuits. The downside is (...)
Hi all, I am doing an input network to match noise figure of a FET, but I get stuck trying to match the low freq of the network to the low freq of Γopt and high freq to High freq. I can match them one at a time, but is there a way to reverse direction on the smith chart? The optimum NF follows a curve (...)
I think, that the sense of that paragraph is: At the receiver after demodulator and before detector a matched filter is usually used (a linear filter, designed to provide the maximum signal-to-noise power ratio at it's output for a given transmitted signal waveform). The main property of the match filter is that the maximum output S/N or (...)
Dear Friends, I am really curious that what is the meaning of simultaneous-match input/output impadances or simultaneous-match input/output reflection coefficients in Agilent ADS . For the LNA design, after plotting gain and noise circles I match the input of the device. Now I need to match output but (...)
Hey I´d like to do a phase noise analysis with cadence virtuoso. In my pss analysis the estimated frequency (direct plot harmonic frequency) does not match to the beat frequendy i´ve entered in the simulation set up file. to set up the simulation i followed the spectre rf workshop. what could be the problem there? regards zitty
Hello naderi, In a delta sigma modulator, it is well-known that only DAC and the first integrator can contribute to the output noise. It can also be tested by behavioral simulators such as Matlab and verilog-A. I found that transient noise analysis is not match with noise analysis. An experienced designer told me that he
who can point out the essential of low noise circuit design? straitforward is welcome and some good examples are also welcome!!! Thank you!
You should use Load-Pull Tuners to find Optimum noise Impedance. By changing Source Impedance, you'll obtain noise Circles and one single Optimum noise match impedance.
Hi!!! =) Im designing a CMOS low noise amplifier and would like to generate the input return loss circles of the amplifier for different values. For example -10 dB, -15 dB and -20 dB. I know that if the amplifier is going to be matched to S11* at the working frequency teoretically the input return loss would be infinity, and is represented as a
Hello, You can see your analyser as a receiver with certain resolution bandwidth. The receive frequency is swept to show you a spectrum trace. To get the real power of the signal that passes the resolution bandwidth filter (the IF filter in a receiver), you should carry out an RMS scheme (that means squaring the output, taking average over time
Generally reactive components (ideally with no losses) doesn't introduce noise in the circuit. There is a situation, for example at the input match of a high-frequency LNA replacing a 0402 cap with a same value 0805 one (due to different parasitics and SRF) the noise figure gamma optimum match could change, increasing the (...)
If you use noise matching the gain drops... The optimum point is where the gain circle intersects the noise circle desired.This will be your gain...
is it mandatory to make out put inpedance of low noise amplifier is 50 ohm
I agree with the posts above but you have also to consider some extra advantages. Your ADC temperature coefficient wil never match the temperature coefficient of your sensor. Placing both at the same place will equalize the temperature of them and you will get a combined temp coef you can manage to cancel out. Also, you can in factory calibrate it
Hi, I currently have some problems with matching the MGA71543 LNA ( ). To match a low noise amplifier, I usually plot the optimum noise match point and maximum gain (=s11* conjugate complex) match point, and then chose a matching network somewh
Hi, I try to match model of first order sigma delta to spectre simulation results, but they disagree! First figure attached is first order sigma-delta model (comparator shown as a summing node and noise source N(s)). Can solve to get: Y = N/(1+H) + H*X/(1+H) where H=K/s So if K/s >> 1, then: Y ~ sN/K + X This says to me that to
Hi Guys, I am new to DSP, I just got TMS320C6713 board and wanted to perform some real application (Signal to noise). I use Simulink to programming DSP board but I don't know how can I run my program on DSP board. When i build my model in simulink gives me an error "RTDX target application does not match emulation protocol Loaded program was
The input PAD can increase the NF of the LNA, detuning the optimum NF match, and also because is picking up more noise from the substrate.
Yes.. noise immunity is the first concern and even order harmonics are much lower than single ended.
Considering power supply noise, if we want to decrease its effect on PLL, should we increase loop bandwidth or decrease bandwidth? If the VCO is composed of transconductor (PMOS)+ICO+power match, I think the power supply noise has the some effect as the noise of loop filter on control voltage, which is a bandpass filter (...)
Hello , everyone. I've designed a mixer based on Gilbert cell, and plan to realize this mixer and test this mixer alone. But I am confused on the input matching work of the mixer now. The RF signal is connected to the gate of the MOSFET whose input impedance is infinite, so I think I can parallel a 50Ω resistor so that input matching is OK.
Good afternoon. I have a simple problem. I checked on the other threads but I did not find anything similar. Basically: I want to filter white noise "w" with an high pass filter of the "n" order. y(z) = (1-z^-1)^n *w(z) But I do not understand why the psd of y does not match the shape of the filter in low frequency. Hope someone can h
The total noise is a root from sum of squares of all noise sources: totalnoise = sqrt(ns1+ns2+...+ns_n)
Yes, it is possible. You need to ?modify? the transistor with a series or parallel feedback. Usually for the purpose the series feedback technique is used because the parallel one will bring much worse instabilities. You have to use an inductor (or a high characteristic impedance line) in the common node of the transistor (emitter or source). You c
Dear everyone: Please check the NF shape of my mixer. It is not normal, it is not smooth. I could not find the reason. Could you help me ? Thank you very
Dear all, I was wondering why an LNA has to be power matched at the input. Is it for low noise performance, or is it to achieve optimum power transfer from the receiving antenna to the rest of the receiver? If the latter is true; what is the use of achieving optimum power transfer? I mean: if the information of the signal is in the voltage or in
hi, as is well known that when lna is well matched, you will get either best power delivery or best noise figure. but now what confuses me is that , a low-input-impedance lna with S11 about -3 is simulated in icfb and I get its gain(gain1) and NF(NF1), and after I match the lna with S11 <-10, I found that the gain is still more or less (...)
Hi all, I want to match LNA input port for noise match smith chart,I can do the match from Zin(Zin=Zopt*) to Zs(Z=50 Ohm) or from Zs to Zin.Which matching procedure is correct?And if i do it for power match,how can i do?what is the difference?And why?:|Thank you.
Okay, so I figured out how to measure noise figure in pSpice, it was simple as I suspected. There is one sticky point left to my LNA design, the output match at 2.45GHz I am supposed to use bond wires and on chip capacitors only to create the output match to 50Ω. My LNA is a cascoded mosfet design. I have an inductor in the drain to (...)
Hello everybody, I'm wondering if it is desirable to design a frequency divider for a frequency synthesizer PLL only with 2^n dividers. Are there any advantages (speed, power dissipation, easy implementation in CMOS, noise,...) in avoiding digital counters or other non divide-by-two blocks? Thanks in advance! Alex
The buffer is not affecting too much the Phase noise but its linearity is important to don?t distort the signal. In general the input impedance of the buffer is high and the output impedance is 50 ohms.
Why is the SAW-filter located in front of the LNA? The insertion loss of the SAW-filter will degrade the noise figure of the LNA.