Cross function cadence waveform. Another recent enhancement is the addition of the original waveform time on markers on the eye diagram. The blue waveform is the PPV plot for the same node. clip and riseTime (and indeed most functions) will cope with families of data as input - the clip function will return a family of clipped waveforms, and the riseTime would give you a plot of the The impedance of a PDN is determined by the arrangement of conductors, dielectric substrate material, and capacitances in a PCB. Jul 29, 2022 · Hi all. This suggests that the phase margin frequency and gain margin frequency are also not defined. These can be the points M3 (start - 104. Ben Wiggins. g. As a results, not a single waveform, but a waveform family has been used. Verilog-A is the simplest way. If you are encountering numerical noise issues, you might add a tolerance to your cross expresssion. Beckett Group Custom IC, Cadence Design Systems Ltd. 9 0 "either" t "time"), where OUT_SF is the output of my comparator and 0. now the problem here is to express the threshold value as a variable of the original signal. information of Cadence or its licensors, and is supplied subject to, and may be used only by Cadence’s customer in accordance with, a written agreement between Cadence and its customer. I have finished the code if the 2 waveforms are single "waveform" (drIsWaveform() ==> t). But what if both the waveforms are random ? How can i know at what time does the 2 random waveform cross each other? is there any direct function which i can use? Regards, Jagdish Use the calculator. Then i will use the time to automatically do the other task too. The first argument to cross is an expression whose value varies with time. After going through this with Cadence Support, there are two CCRs filed: one for documenting the private functions (CCR 2746318), the other one for having a way to rename waveforms from Skill (E-CCR 2745576). Language SKILL Date Jul 14, 1999 Modified Dec 10, 2007 By A. Mar 6, 2018 · Thank you for your kind reply. Thank you for your promote response. /* abDumpWaveform. Per the manual (Virtuoso Visualization and Analysis XL User Guide, Calculator Functions, Special Functions, dnl), the calculation is pretty much what you have said. Jan 24, 2021 · This is a result of the fact that the propagation delay of an inverter is not only a function of device sizes and load impedance, but also a function of the transition times of its inputs. Let's say that I want the voltage value when t = 3ms. Figure 1: Measuring Transistor ft. For example, if you create a set of corners as a temperature sweep (remember, the definition of corners in ADE XL isn't restricted to PVT--you can create a variable out of pretty much anything and then sweep it in the Corners form), you can create a MAC expression using the cross() function i. I can get my output waveform as expected. With an ideal 100 MHz input waveform from a 10 ps transition time analogLib vpulse, your input transition times to the first inverter contain far more It would be helpful to share what you tried that didn't work when you tried the dnl () function in the the waveform calculator. So you should be able to do: ymax (mag (Vgain)) or. 2) Then hook up two ports. out") abDumpWaveform(VT("/c") "data_c. Hello, After plotting a waveform in ViVA, I am aware that you can export the waveform points into a CSV file. This document is meant to be a quick introduction to the basic use of this calculator by going over a basic application. 1V to 1. com) abMakeWaveform() the second argument should be a list. However if I do the same with the calculator using waveVsWave, it will get the waveform families wrong, that is, it will connect the points to the points of another waveform instead of its own Jan 18, 2023 · Still need help for options to use with xrun and irun commands. I created a simple inverter and used xmin and xmax of the output signal. Most important is that I do not need to mention them separately. Jan 31, 2022 · The thing is, i'm saving the whole wave, the time values + the voltages, but what I really need is 1 value for a specific timestamp. Use the Calculator cross() function to locate the times at which your signal of interest crosses the voltage threshold you are showing in your figure. Cadence Calculator Expression. xmsim worklib. 5V of the first waveform to the fifth Mar 7, 2024 · Even if the PWM waveform is a perfect step function, the MOSFET’s Coss value will set the lower limit on the turn-on/turn-off time. I am trying to find out the Vih and Vil levels for my design. Feb 18, 2022 · The cross() function with the arguments stated above finds the first x-axis value where <your_slope_signal> crosses 0. There's also a period_jitter function - which can do the period versus time or cycle number. . tcl: Jul 16, 2008 · To calculate ft, plot the current gain by dividing the collector [drain] current by the base [gate] current and then using the cross function to find the unity gain frequency. Potentially you could have used an existing Verilog-A model for a DAC, and then maybe an ideal ADC to drive that, but then you need the "cross" can get me the array of times I would like to sample, but I can't find a function that gives me the value of another analog waveform based on this array of times. dnl [k (or maybe k+1)] = (sig [k] - sig [k-1])/ideal The frequency function will tel you the average frequency of a transient waveform - so you'd want to leave it to settle, and then clip out a few cycles and use frequency. ymax (db20 (Vgain)) Those should work fine. I want to measure the voltage of vin whenever vout crosses a certain threshold, e. Suppose I have an instance with input signal vin and output signal vout. Sep 19, 2019 · The ?overall t is added whenever you use the "measurement across corners" (setting eval type to "corners") because had the inside of the ymin be a waveform, this would find the minimum across all the individual curves and families of curves. RAK. Related Resources. Mar 23, 2021 · I just tried an example value() function on a waveform from a simulation I performed in Assembler using a variable "sel_tdel" and printed the result to a table. Alternately, you could append the result to a table or select the waveform in Figure 3 and export it. Oct 24, 2019 · Analog waveform from an EKG monitor. I would like to check these waveforms to see if there is any frequency point "f0" satisying: 1) a_w(f0)<0. A very simple way to do so is to define a simple veriloga model that performs the function 1/s. I'm using cross() function to perform measurements in the following way: I am using ADE, IC5141. input_waves. dir (real) – direction (use +1 for rising, -1 for falling, 0 for either) ttol (real) – time tolerance. Newest. I thought you wanted to view the dnl() function output - amd I incorrect? 2. The value function will tell be the value of the particular output at time given. So the 1st and 2nd row in settling time function is: y, value is -1V . I don't think it can be used to draw the integrated waveform. , bandgap voltage, Vbg). Aug 20, 2019 · To find the settling time of WAVE1 to P% of final value: Clip the WAVE1 at the extremes of where the settling event occurs. But, I want to find out the settling time from -1V to 1V at 0. Mar 19, 2023 · The red waveform is the transient waveform for an output node for my oscillator. I have a time domain simulation from 0s to 32us (x-axis) and 0V to 3. ,if a function is ƒ, then its inverse function is ƒ −1 . tcl. PSpice integration offers an easy route to cross-probe designs for circuit simulations. 6V. If you are looking for the instantaneous mean of a waveform, you'll probably have to write your own skill routine to do this. Figure 1 suggests the use of a variable with your syntax evaluates properly. from the mid point of the input waveform to the midpoint of the output waveform. Cadence Virtuoso ADE Suiteは、アナログ、ミックスシグナル、RFデザインの探索、解析、検証のための業界をリードするソリューションです。. You can write calculator functions such as: t1 = cross ( v ("PAD") pvdd/2 3 'rising) t2 = cross ( v ("OUT") 0. 1. How do I perform a clip along the y-axis? I'm trying to separately take the integral of all positive values and all negative values of a waveform, and vertical clipping is how I thought I'd do it. 2) b_w(f0)=0. If doing a parametric sweep, you may then find that VAR() is returning a waveform - depending on the version you have, this might cause a problem when used as the interpolation value of the Hi Andrew, Thank you for the reply. Mark Feb 20, 2017 · Hello, I would like to create a function that performs ideal aliasing on the output waveform of a simulation (particularly output noise). Dear all, I have a problem in finding the point (RL_opt) for which an output variable (dg_calc) is equal to a certain value in a parametric analysis. Now, go back to Cadence Analog Design Environment window and verify that your window looks like the picture below. Andrew, Thank you for replay. For instance, the below two are the plots I got for swapSweep function to plot two output expression in ADEXL(or same for Assembler). il Author A. When you start examining the effects of filter, amplifier, and component bandwidth on digital signals, you start to realize their connection with the analog world. Expression 1 : (VF ("/vin")/IF ("/V4/PLUS")) provides me with a wave plot of input impedance v freq which is fine but for quick verification the histogram is more useful May 9, 2022 · Oscilloscopes measure parameters of time-dependent waveforms (periodic, transients). It is shown in square brackets after the eye time value. D. It would process 2 waveforms. Regards, Andrew. In other words, I want all the nyquist bands within a specified frequency range to be folded down to the first nyquist zone. I hope I have explain the situation clear. When using cross function in calculator, values are plotted on waveform window instead of being shown in value field. When I use xmin and xmax of the output signal with Nth Minimizer value equal to 1, I get the value corresponding to it. Put another way, the desVar() defines the variable before the simulation is run, and the VAR() function refers to the value from the simulation itself. Beckett A simple function to throw together waveforms for test purposes. 2 3 'rising) delay = t2-t1 fprintf ( of "%g", delay) To print the delay between two signals Jul 7, 2004 · v_naren. Oct 2, 2020 · I figured out the swapSweep function but it is not consistent in terms of sweep point order in the x-axis. a_w(f), b_w(f), c_w(f). What precise arguments did you give to the cross function? Regards, Andrew. 5us) and M4 (end - 113us) for the above shown waveform. Subtract one signal from the other, and then use the cross function on the result. Cross spectral density is a method for comparing the power spectra for two signals. This is about ADE smulations. I have highlighted the flat-ish part of the transient output but the PPV plot is not 0 (neither constant) for I am using SimVision 15. The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. It says "Applies a function with a set of arguments to each member of a family". Hi. Your waveform does not cross 0. Jun 27, 2020 · For example, I would like to have a staircase function from 1. I checked manual for function famMap. Other than that for pulse width, you'd probably have to write something based on the cross() function using a bit of SKILL. If there is no way to do it using the built-in calculator, I would like to write a custom SKILL calculator function to implement this functionality. I met some difficulties when the input waveforms are "family" (famIsFamiliy() ==>t). My output waveform goes from -1V to 1V. Calculator. You can see from this image that the X point in the square brackets above is the same as the X value below. Is there a way to save only that voltage value and not the whole simulation? Then you can use the riseTime() function in the calculator with the waveform as input (you might want to use clip first to clip out that edge). out" "%e %e") ;; exponential format abDumpWaveformSplit() is May 24, 2021 · In Figure 3, I then apply the xval function to the result with the Calculator expression and plot the result in Figure 3. b) Use SpecialFunctions->delay set as follows and then click OK. In general, there are five types of harmonic distortion that can be observed when looking at a waveform: Amplitude distortion. The idea is to find voltage at which current in maximum. If you need to know the y-value of the intersection, use this cross expression as the argument to the value function on one of the two input signals. I perform a DC simulation and I defined two different scalar outputs (let's say O_1 and O_2). It's a scripting language that works behind ADE. The block has 5 trim bits, and for each trim code, I want to sweep the temperature (say -40 to 125), and determine which trim code produces lowest Vbg spread over temp. It is possible to clip a waveform along the x-axis using the clip function. Further more,if ƒ(x)=y, then x=ƒ −1 (y). Multiply the output from Step 1 by the time-domain input voltage waveform (converted to an input power) Calculate the convolution between this product of time-domain functions. Make sure only 1 settling event occurs in the clipped waveform and the end point is what the final value you are looking to Jan 26, 2024 · Dear community. After running ur simulation and plotting ur results, from the Analog Design Enviroment choose save state (with ur waveform window OPENED) and there are some check boxes which will let u save the current waveform. what I mean by "inverse function" is a function that undoes another function. Finally, I find the method to use "apply" functions, then I can put the arbitrary number of waveforms as the direct argument in the "famMap" function. You can specify a starting point, an ending point, type of sampling (linear vs log) and the interval between samples. Usage: abMakeWaveform ('cos linRg (1 100 1)) => o_waveObj Returns a waveform with x axis 1 to Activity points. I am trying to measure the propagation delay low to high which is the delay time between the 50% transition of the falling input voltage and the 50% transition of the rising output voltage and I enter in the delay special function: My input is A and my output is Z. If you wanted the pulse width, I guess you could do both versus cycle number and then multiply together (and divide by 100). Regards, whusteryzh Finally, with respect to the use of the cross() function with DC analyses, I did find a recent Troubleshooting article that pertains to an issue, but it appears your expression does not conform to the failing case they note. Phase distortion. to measure the low to high delay time I must use the second falling edge of the input and the Dec 11, 2020 · The dnl() and in() functions provide different results. With two high-resolution measurements and some post-processing, you can determine your PDN Jul 5, 2021 · If you were to draw up a small-signal model of your test bench and compare it to the small-signal model of the cross-coupled pair, I think you might note the following: a. I think Value and Cross function can help me but I am not sure how, as in cross I have give the threshold value. Aside from nonlinear distortion produced by nonlinearity, these types of harmonic distortion will only be seen on broadband Feb 23, 2018 · Original Waveform Time. [/b] K. This opens the Add Custom Calculator Function form, just add the path to the file you've downloaded and click OK. Can this be evaluated ? Votes. 20-s024. Signal integrity, power integrity, EMI, and circuit design often involve signal . Sep 10, 2019 · I have a question about the use of calculator functions. e. However, I am performing a Parametric Analysis and Export Waveform to CSV Fille in OCEAN Script - Custom IC SKILL - Cadence Technology Forums - Cadence Community May 5, 2023 · I followed previous posts on the topic and I receive an error: 1) Calculator function to measure the value of a waveform when another waveform crosses a threshold (cadence. Return type: event. enable (real) – enable. 3V (y-axis). 1) Setup a proper biasing circuit first. In my simvision session, I set the trace type to "Digital" since the default "Analog/Linear" format is not as useful and very space consuming. When creating a simulation test bench the natural place to start is the actual For example, if the open loop phase does not cross -180 degrees, then the phase margin is not defined. Before running the Monte Carlo analysis, I do a simple dc simulation with Spectre. Maybe I didn't explain myself clearly,due to my poor English. How are you plotting it? Given that it's just a single number, why would you plot it? Feb 9, 2012 · Perhaps not so obvious is the fact that you can use other functions to measure across corners as well. There is no 50 ohms source impedance in the small-signal model between the two device drains b. An example of calculating ft, is shown in Figure 1. Wondering what What controls "Value" vs Plotting on waveform window. I take a look on the existing example of the special function, there the "family" waveform is handle by "famMap()" function. Convert S-parameter data for crosstalk (NEXT or FEXT) to time-domain data with an inverse Fourier transform. Setting up an oscilloscope is slightly more complicated than a multimeter, but allows for far greater analysis of signal characteristics. functions, and behavioral devices • Determines which components are overstressed using Smoke analysis and by observing component yields using Monte Carlo analysis Features Cadence simulation technology for PCB design integrates seamlessly with the Cadence front-to-back PCB design flow, making it possible to have a Jan 12, 2023 · If it were to start 180 degrees out of phase from the green voltage waveform, then the "B" measurement will result as the rising and falling edges of both the current and voltage waveforms will have swapped with the phase change (i. Oldest. 6. If the edge number is 0 (forget about the fifth argument onwards which allow you to return single or multiple values), then it returns a SKILL list (not a waveform) with all the crossing points. I want to get a vector of pulse width values for a non-periodic square signal using Calculator. Sweep order is same in the simulation setup but x-axis order sometimes gets messed-up run-to-run. For instance, Custom WaveView can read-in the analog results of an HSPICE® simulation, convert those waveforms to digital (single or multi-bit Jun 28, 2023 · This is often the case that will result in detecting a "rising" (or falling) cross event on what appears to be a "falling" (or rising) waveform transition. 3. For example: in a TRAN simulation of an SC amplifier I get input and output waveforms Vout(t) and Vin(t), and use waveVsWave() to obtain a plottable "Vout(Vin)" waveform. Beckett Functions for dumping a waveform to a file Examples: abDumpWaveform(VT("/c") "data_c. Cross spectral density is also related to other signal comparison metrics, and signal processing engineers should understand which metrics are best to use in different situations. May 13, 2018 · The problem is that using the "deriv()" function doesn't work (I guess) because the X and Y values of such waveforms are not properly arranged. I was trying to use the cross() function but it doesnt work for what I want. Suppose that the signal is simply called vout and the corresponding waveform is VT("/vout"). value is used to get the value of a waveform at a single value or multiple periodic values and each axis can be interpolated in a different way for WREAL I am exploring the special functions in IC 6. Expression Builder . Introduction: The Cadence Calculator is a powerful tool inside Virtuoso that allows you to apply a wide variety of mathematical formulas and functions to signals from your schematic. "psin" from analog lib and then run a s-paramter analysis over the frequency range for which the model of the MOSFET is valid 3) now after simu plot y21 in magnitude or in dB then find the frequency at which the mag/dB are 1/0dB respectively and u get fT You can't take the ymax of a complex-numbered waveform - you have to transform it to a simple value versus frequency instead. Virtuoso Studioプラットフォームの不可欠な部分として、完全な設計検証に必要なシミュレーション・スループットの大幅な If the crossing number is passed as 0, it should return a list of the crossings rather than a waveform. 2) convert a waveform to a list: SKILL: How to convert a Cadence Calculator Basics. For a start, calculator functions produce a scalar, waveform or family of waveforms from (mostly) existing waveforms and other data (occasionally they'll do so by reading data from disk somewhere). So lets say I have a triangular input waveform and square output waveform (in phase) and I am trying to find the points at which the rising and falling edges cross. tol (real) – waveform tolerance. Jun 28, 2023 · The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. 1 day ago · wave (real) – look for zero crossings in this waveform. I have a set of signals which are of type real that I am looking at in simvision. Not sure if there are other situations, but this will certainly be the reason in this case. Then, run the simulation by selecting the green light icon or by selecting Simulation -> Run. Cross over distortion. Best Regards Yi Type 'ESC' to exit the waveform select function. Frequency distortion. I'd like to use "cross" function in ViVA calculator to find specific time at digital event transition. i. I think that this function just " calculates " the value of the definite integral of the given signal on the specified interval. 3) c_w Jan 4, 2024 · The second derivative of a waveform can be very "noisy", so using the integ() function with extrapolation "on" leads to inaccurate results if the final value lies outside. I am trying to plot a histogram of Input Impedance (mu and sd) of an amplifier over 200 MC runs at 100KHz. I tried that it works fine for single bit digital signal. Beckett Group Custom IC (UK), Cadence Design Systems Ltd. testbench \ +access +r -input input_waves. I am actually writing a script based on the cross function, i would be able to get the time where the V("/OUT") is crossing the value 0. I'll happily provide some context. Aug 29, 2005. You might try plotting the open loop gain and open loop phase from your analysis and visually inspect the two to verify the existence of a phase Hello, I am having a problem to extract values from time domain simulation. Mar 11, 2022 · 1. There are many waveform intersections and hence the result appears as a waveform. however I really would like to have a waveform among the outputs in order I can plot them across corners/sweeps in the Results Browser. One thing I always use to bypass the Cadence calculator is use Ocean to simulate my designs. Mar 2, 2022 · The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. Dec 3, 2005 · integration in cadence calculator. 4,111. We like to treat digital pulses and analog waves as belonging to completely different realms of electronics design, but this is not really the case. All PDNs can exhibit an underdamped oscillation and complex resonance response when excited with a broadband current pulse. Thanks and regards, Ivick. 0 and returns this value. 2% settling time. Andrew Beckett over 9 years ago. for xmsim: Please correct me if I am wrong. I did in the following way, but the operation is performed only in the points in which the function is calculated during the parametric analysis. 9 is my threshold value. Notes from my wiki about Sep 21, 2020 · When I right click, on the results tab, the gmoverid result and plot all, it will plot correctly the gm/id curve in function of either W, L or vgs. Is there a simple special function to define the output O_3? If there is not how can I define such an output? This is using this code: /* abMakeWaveform. Jun 19, 2020 · The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. I am simulating my design for a sweep in a range of different VDD values and I need to find the delay for a huge number of waveforms combined in a "family". if one of the waveform was constant, I would have taken the average value of it and compare the 1st waveform with these average value using cross function. Then the 3rd and 4th row in settling time function is: y Apr 26, 2017 · sample () is (typically) used to sample a waveform at a different rate. To clarify, are you looking for the end average value or are you looking for the average of the waveform at each point in time? The end-average value can be calculated with the average() command. For example, I add getData("/WWL" ?result "tran") as a family of waveforms in signal1. The output from Step 3 is a power waveform; convert this to I was replying from memory - what I called "crossing number" is referred to on the cross form as "Edge number". Alternative arguments to cross(0 will find all the x values where it crosses 0 as a waveform. Or you could use freq() to get the instaneous frequency versus time. I use the settling time function in the calculator. a) Click on vt. Rather than using cross and ymax, use xmax instead: Aug 20, 2019 · To count the number of edges that cross a certain threshold use the following expression: drVectorLength(drGetWaveformXVec(cross(clip(VT("/RO") 30e-6 31e-6) 1 1 "either" t "time"))) Here it will count the number of edges (rising and falling) crossing a threshold of 1V for the signal /RO in the time of 30us to 31us. Then in the schematic window select the output node and then the input node, in that order. I can extract the final value of the x-axis with some workarounds, e. The Waveform Window will appear if it is not already open with the signals that you Feb 2, 2018 · From the webpage, first download the function you want to use and then open the Calculator or Expression Builder and click the respective Add Custom Function button, as shown in the figures below. 0. I am using IC6. It has been discussed in literature that for the flat part of a squarish waveform the ISF will be 0. You might also take the derivative of the waveform to spot a change in slope polarity. I have two additional questions: 1. Since this wasn't a SKILL question, I moved it into the Custom IC Design forum. Oct 20, 2014 · For this, I am using the 'cross' function from Cadence calculator. cross (deriv ( some current ))) ymax (deriv ( some current ))) 1 "either" nil nil) The plot is for derivative of current (y-axis) vs some voltage (x-axis). As an output of an s-parameter (or ac) simulation, I have three custom waveforms a_w, b_w, c_w which are all functions of frequency, i. falling edges of non-inverted waveforms will appear as rising edges). Machine SUN Date Oct 23, 1997 Modified Jan 31, 2005 By A. 36. May 2, 2020 · It's far from clear to me why this would be useful to have as a calculator function. When you changed to the inl() function, you set the ?mode to user, but then set the value of ?threshold to 0. This computes the delay from the fifth edge rising past 2. Eye Diagram; Blog The purpose is to use Skill or OCEAN to post-processing AMS simulation (by irun) output waveform and do some auto-checks on signals in digital domain. JustinTaylor86 over 11 years ago. The expression I use is the following one: cross(VDC("/OUT_SF") 0. Except as may be I am sure the data and signals are right because I have developed other similar function but dumping xaxis and dely_data into a textfile and I am able to see the expected results. Whereas, when I have the value of Nth Minimizer equal to 2 or more than 2, I don't get the expected result. I have a block the output of which is the signal of interest (e. Custom WaveView is a full analog and mixed-signal display and analysis environment, reading simulation results from either analog or digital simulators and allowing complete conversion between views. I saw examples of famMap usage like you described. If the Coss value is too large, it could cause the turn-on or turn-off time to be longer than the dead time and the timing between commutating PWM pulses. You can create a waveform of the threshold crossings and either plot them as a function of time or cycle number. Now, I would like to define a new scalar output O_3 which is the minimum value among the scalar outputs O_1 and O_2. Intermodulation distortion. 4V with step size 100 uV. oxlhqabuchpnmklirhtw