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23 Threads found on Dft Calculator
Hi guys, I am not familiar with dft of calculator in cadence spectre. The problem is in frequency domain i observe very low resolution and steps are 200Mhz ! how can i increase resolution ??? 132731 I have a 2.5 Ghz signal and i cannot observe it ! and neither other tones !!!
Ok so I get the transient response of the output of my circuit and i want the Power spectrum. I ve been using dft from the calculator but shows the voltages of various frequencies (devided by 2 as i figured out) and not the power. Is there such an option so that i can see the power of each frequency in dB and dBm? this is what i get using the ca
Hi, I am trying to take FFT of a time domain signal, at differential LNA output, from 100nsec to 200nsec using spectre ADE calculator. However, when i try to evaluate the fft, following error appears. Can anybody suggest what can be the reason for it. Warning - <calculator> Evaluation error(ERROR : ("putprop" 1 t nil ("*Error* putprop: fi
As you might know already, in Cadence Spectre, we can plot the spectrum of a signal (say, output of an amplifier) using "dft" function of the calculator.Don't mix up Simulation with Post Processing. They are completely different phase. It is an issue of Cadence Post Processing Environmen
Dear all, I am designing a low-to-medium S/H circuit for an ADC. The sampling switch is a bootstrapped switch to linearize the on-resistance. I first designed a bootstrapped switch, and I simulated the waveforms and obtained dft and THD in cadence with the calculator. After that, I also designed a dummy switch to cancel the charge-injectio
What device are you talking about? Amplifier, ADC, DAC... in general, you just divide the output by the full-scale (normalize to the full-scale) before taking the dft so that it corresponds to /=1->0dBFS
Hi! using the calculator tool, you can calculate the dft of the signal but take the freq range 1kHz say on both sides of the harmonic you are going to calculated. Then you can use the peak function to get the harmonic. You can do this for calculating all the required harmonics by adding the output variables for each. Then by doing t
Hi there, I am trying to measure my 10 bits ADC ENOB. My input signal is 7.5KHz sine wave, sampling frequency is around 552KHz (required by application). And output is the sampled data through dac (written in veriloga, no filter). First, I selected my input signal and do the dft as, From 30u to 1m (did transient simulation from 0 to 1ms
Hi all, is there anybody who can provide some tutorial for dft flow, because I see different results with different dft setting, so I need a detailed dft flow literature, better from how to set up the transient analysis, to how to get a correct frequency response with dft function. Thanks in advance, best regards
I am doing the dft analysis to an ideal sinwave using the calculator, I use the conservative to run the tran analysis,but I get a result of only 55db for an ideal sinwave. So can anyone tell me what's wrong with my simulation, what is needed to be set in the spectre ? Thank you very much. the sampling frequency i used was 200M, and the freque
Doesnt the freq command in the calculator do the job for you? It plots the running frequency. Or else if you want to take the fft, use the dft function (fft is just an algorithm to do dft) and indicate the window over which you need the dft to be done. Or run a pss sim to get a very accurate spectrum.
In amplifiers, if the input signal frequency is low enough, I would suggest avoid transient sim (+dft) or flex-balance (just like HB) in Spectre(RF). The easiest way is to use DC simulation, and through VerilogA function and calculator to find the Fourier series coefficients. You can obtain much more insight in DC sim and avoid possible settling
THD is the value harmonic energy versus the basic frequency energy. To test the THD,you could use the tool box THD of calculator. Moreover,you could run dft of the test signal.Then read the mainly harmonic dB energy minus the basic frequency dB energy.
you can use calculator's dft in cadence, or use SpiceExplorer, the inner function of FFT is very convient.
Yes, indeed the zero crossing is missing some accuracy. I think spectre could be forced to set a time step exact at the zero crossing of I and Q signal. But there is another method. Take the FFT or in the case of cadence calculator dft of the I and the Q signal. The calculate the difference of the argument of the complex number result of the fun
Before doing the dft, we shall do the sampling first. Because the time steps in Spectre is not equal, we have to resample the resulted waveforms and make the time step equal. I remember in doing the dft, we shall specify the sample number in every dft operation. The whole dft operation is divided by several small (...)
How simulation SFDR?please tell me Use the dft, you can find it in calculator toolbox. setup the start, stop time, internal, window, etc. you can measure SFDR by max harmonic
Using dft of calculator function,and you can get HD3 and SNDR.
hello, i was doing some simulation in cadance tools , and i needed to view the spectrum of certain node ,so i did dft from the calculator but the program needs some data >>to,from and samples i was wondering how can i choose the values for these parameters correctly . and also what is the diffrence between dft and (...)
Not sure if there is a solution, or this is routinely done, but ripple gives rise to spurs and phase noise is not directly affected by it unless ..... read on run a dft using calculator on the vco output while the PLL is locked. This means clipping the waveform when it is locking. You can see where the spurs are and their level in dBc. If the