I need to plot a line at y=-3 on my graph that has two functions plotted on a log scale on the x axis. loglog - logarithmic plot In this example we are going to demonstrate how to use the ' loglog ' function included in Matlab to produce non-linear plots. [C, h1] = contourf(X, Y, Z, 'ZScale', 'Log'); clabel(C,h1); and get the picture at the bottom with labels 10, 10^5, 10^10, etc. I know about semilogy, semilogx and loglog functions, but I'd like to understand how to perform conversion from linear scale to logarithmic scale manually, i.e. The graph will be linear with a logarithmic y-axis. digital filter freqz plot. Can anyone help me please to do this? Sign in to comment. Sign in to answer this question. x = [1 0.1 0.01 0.001] y = [10 60 120 180] I want to plot x-axis in logarithmic scale. I am wondering how to plot in MATLAB with a logarithmic scale. I am wondering how to plot in MATLAB with a logarithmic scale. However, I would like to have linear scale (0-1 for the y-axis), is it doable? The most common base of any logarithmic equation is always considered to be 10 if it is not specified. The first is to use the plot command to plot log(y) vs. log(x) on a linear scale. Based on your location, we recommend that you select: . Sign in to answer this question. An frequently-used method is transforming data by the formular t = sign(x)*log(abs(x)), then plot the (t,y) instead of (x,y), and modify the yTickLabel manually. There are two ways to make a log-log plot in MATLAB. Without the logarithmic scale, the data that we plotted would show a curve with an exponential rise. Can anyone help me please to do this? When you set YScale to log, then internally it would take the log of the negative values you have, and would found that the log is complex. If you use xlim([5000 8000]) the plots are superficially the same because the range of x-values is so limited the difference in scaling between the log and linear axes isn't much at all. Sign in to comment. Choose a web site to get translated content where available and see local events and offers. MATLAB: Linear Scale of a Frequency Response Plot (freqz) – Digital Filter. Introduction to Log Plot Matlab. These are my data. That’s all that needs to be done to plot a graph with a logarithmic scale. The scale is very useful when displaying the data over many order. Show Hide all comments. plot( log10(x), log10(y)) Alternatively, you can use the loglog command to make a plot with log-scale axes: loglog( x, … The log of negative real values is equal to the log of the positive value, plus (pi*1i) -- that is the result is complex. without embedded MATLAB functions. 0 Comments. Show Hide all comments. 0 Comments. Problem is when I can have one or the other, y=-3 and my function or I can have an x axis log scale. This term refers to the fact that the plot is logarithmically scaled in both axes. If yes, please assist me how to do it. Select a Web Site. Hey guys I'm blundering through MATLAB here, I haven't officially learnt it and my Lecturer expects me to know how to use it. These are my data. Summing up, I need to do one of the following: Find a way to set the logarithmic scale programmatically and let matlab worry about the isolines. Similarly, you can apply the same for x-axis by using pyplot.xscale(‘log’). Mar 18, 2019 The freqz(z,p) gives the plot of magnitude in dB (log scale) versus the normalized frequency. Logarithms can be written as the inverse of an exponential equation. Log Plots are the two-dimensional graphs that have a logarithmic scale in both horizontal and vertical axes. x = [1 0.1 0.01 0.001] y = [10 60 120 180] I want to plot x-axis in logarithmic scale. 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