Question

How to incorporate multiple IF conditions to generate noisy data?

Hello, I wanted to simulate a signal which has noise in the form of spikes (both positive and negative). If a single IF conditio...

2 months ago | 1 answer | 0

Question

Error in opening a data file with cdf extension

I have been sent data file with a .cdf extension. It is supposed to contain time and light absorbance data. When I use the cdfre...

3 months ago | 0 answers | 0

Question

How to generate a vector of a shifted impulse function?

Hello, Suppose we have a time vector x=0:0.1: 50. I would like to have a delta function at a non-zero position, say at 25 with u...

7 months ago | 1 answer | 0

Question

How to extract certain rows and columns with the readtable option for Excel files.

Suppose we have an Excel file Data.xlsx. The file have certain descriptive text in the initial rows and then there is tabular da...

1 year ago | 1 answer | 0

Question

How to convert or extract arrays from a structure?

In continuous wavelet analysis, when we export the coefficients into the workspace, the data is exported as a structure (1x1 str...

1 year ago | 1 answer | 0

Question

Integration via trapezoidal rule in various sections of the same array

If the signal S consists of several peaks as a function of time, is there a way to assign integration limits for the trapezoidal...

1 year ago | 1 answer | 0

Question

Generating Approximations from "appcoef" in Wavelet Toolbox

I have a question regarding the MATLAB example for "1-D approximation coefficients" https://www.mathworks.com/help/wavelet/ref/a...

1 year ago | 0 answers | 0

Question

How to replace complex numbers in a column vector with 0.000+0.000i ?

Image we obtain a fft of a signal and we wish to remove certain frequencies from the signal. I want to fill in zeros after remov...

1 year ago | 2 answers | 0

Question

Finding several local maximum values in a given range and corresponding indices

If we have a dataset "y" which consists of a sum of 5 gaussian peaks as function of time t, there will be 5 local maximum value...

1 year ago | 2 answers | 0

Question

How to locate the index of the maximum value in a given range

Suppose we have two vectors t= [ 1 2 3 4 5 6 7 8 9 10 11]; % time values y = [1 2 3 4 5 7 5 4 3 2 1]; % a dependent variable...

1 year ago | 1 answer | 0

Question

How to implement a formula involving several elements of the same vector?

Suppose we have two row vectors Time = [ 1 2 3 4 5 6 7 8 9 10]; width= [0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0]; % width of p...

1 year ago | 2 answers | 0

Question

How to add non-numerical axis values in 3D scatter plots?

I am using a 3D scatter plot option. Can the x-axis values be labeled as "1:1, 2:1, 5:1, 8:1, 10:1" as peak area ratios? Current...

1 year ago | 1 answer | 0

Question

Reading Selected Columns from an Excel Using the "readtable" Option

If we have an Excel file, and instead of selecting a range of columns, I would like to select certain columns. The following syn...

1 year ago | 1 answer | 0

Question

Labeling the columns in an array

If we import a .csv or Excel file using readtable, and then convert the table to an array as the following: Data=table2array(re...

1 year ago | 1 answer | 1

Question

Correct choice of one sided frequency axis after fft

There are a lot of queries on fft frequency. I guess the following point not discussed anywhere explicitly (at least at one plac...

1 year ago | 0 answers | 0

Question

How to replace numbers in a column vector after certain elements?

How should we proceed if we have a column vector X with 1000 elements, and we wish to replace all the values after a certain row...

1 year ago | 1 answer | 0

Question

fftshift with even and odd number of data points (scaling the positive and negative frequency axis)

If we wish to draw double sided frequency axis, i.e., positive and negative frequencies with odd and even number of data points ...

1 year ago | 1 answer | 0

Question

How to add labels to an array or table (after conversion from an array)

I have an array of 2000 x 4 data points. I would like to add labels to the columns only. For example, Column 1 should be 'time/m...

1 year ago | 1 answer | 0

Question

Assigning indexes in an array and finding max values in a selected range

If we have X = time series data and signal in a 8000x 2 array (Matlab 2017b). The first column is time and the second column is ...

2 years ago | 1 answer | 0

Question

Frequency scale in fft after zero filling (odd/even number of data)

Product: Matlab 2017b If we have data set "A" which consists of time versus light absorbance.There is another set of data "B"....

2 years ago | 1 answer | 0

Question

How to combine sections from Workspace into a new vector?

I have Matlab 2017b. 1) If we have two vectors A and B, in the workspace (1000x1), each of same dimension. How can one combine...

2 years ago | 1 answer | 0

Question

Creating Timetables: Error Message in SampleRate

Hello, I am trying to use a suggested function to generate a timetable with a sampling frequency of 200 Hz. tt = timetable(rand...

2 years ago | 1 answer | 0

Question

Doing averages in blocks for downsampling time series data

One way to downsample is to do averaging in blocks. I had asked a question here "I would like to downsample data simulated at 20...

2 years ago | 1 answer | 0

Question

Command for filling in zeros as powers of 2 for FT

If we two sets of signals (A and B) of unequal length, I am using zero padding first to make the length of B equal to A by using...

2 years ago | 1 answer | 0

Question

How to treat a given column in a sheet from Workspace as a variable?

I am generating exponentially modified Gaussians (EMGs) from a simulation and wish to do FT on a selected sheet in the Workspace...

2 years ago | 0 answers | 0

Question

How to read two Excel files and assign columns as variables in MATLAB?

Hello, I am using MATLAB 2017b. I have two Excel.xlsx files, call them A and B, containing time vs. instrument signals under two...

2 years ago | 1 answer | 0

Question

Area under multiple peaks (Exponentially Modified Gaussians)

Hello, I have numerical data from an instrument (time vs. absorbance) consisting of three overlapping peaks (attached Excel). Is...

4 years ago | 1 answer | 0