Community Profile # Jan Orwat

### StethoMe

Active since 2013

Primarily dsp engineer, algorithm developer for sound processing for IoT.
Hardware production specialist focused on prototyping, device testers designing and manufacture as well as introducing product for mass production assembly lines.

Programming Languages:
Python, R, MATLAB
Spoken Languages:
English

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How to fit a different scale to an existing plot
Check if <http://www.mathworks.com/help/matlab/creating_plots/plotting-with-two-y-axes.html this article from documentation> hel...

6 years ago | 0

I'm trying to count the number of times the gui is being run on clicking a pushbutton. How to make the count continue even after the application is closed and started again. (i.e) if the count is 8 before closing ,it should start from 9 the next time
You may specify delete function which will be called each time application/gui is closed. Using this you may save all the variab...

6 years ago | 0

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How to remove a pattern in a table column
assuming T - your table, and n - number of column containing these strings you can do as follows: T{:, n} = regexprep(T{:, ...

6 years ago | 2

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How to do a fft from a sine signal with hanning function
You can try starting with something like this fs = 44100; % sampling frequency T = 1; % period, 1 second n = T*fs; ...

6 years ago | 0

Working and non Working hours
Yes, you can. For example: % assuming your data in variable called datecolumn daytime = timeofday(datecolumn); openi...

6 years ago | 1

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Algebra function with table and vector
If you want to work on tables in MATLAB functions <http://www.mathworks.com/help/matlab/ref/varfun.html varfun> and <http://www....

6 years ago | 1

Interpolation and getting errors
Note, you are trying to access |time(0)| when |t<30|. Matlab index arrays starting with 1. Probably changing |floor(t/30)| to |...

6 years ago | 0

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how can I join points along a two plots with straight lines?
add at the end something like that: hold on plot(reshape([x,x,x].',1,[]),reshape([ytop,ybot,ytop*NaN].',1,[]))

6 years ago | 0

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Please how can I unstack a column of negative and positive values into 2 columns of positive and negative values respectively?
You can compare your data with zero. This will classify your data and you can use it to get what you want. Example based on y...

6 years ago | 0

How do I set my axis values down to zero when changing my y-axis to log scale?
There is no zero on log scale. Add one line on the end of your code: ... set(gca,'yscale','log') ylim([0.4, 3]...

6 years ago | 0

FFT and IFFT Problem (numerically and analytically result is not same)
This is caused by side effects of digital domain # You are calculating circular convolution instead of normal one. To make co...

6 years ago | 0

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Creating HDF5 file: How to create a GROUP inside a GROUP?
Use <http://www.mathworks.com/help/matlab/low-level-functions.html Low-Level Functions> such as H5G.create to create custom/nest...

6 years ago | 0

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What are the disadvantages of using uppercase 'W' in fopen compared to lowercase 'w'
I guess some memory is used for buffering purposes. There should not be *any* differences in written data. 'W' or 'A' are faste...

6 years ago | 1

What is wrong with my code
Are _TH_max1:3_ scalars, vectors or arrays? _&&_ and _||_ may be used only with scalars. Try: if(all(TH_max1(:) >= 0.4) && ...

6 years ago | 0

how to find integral for this function
In MATLAB there is a difference between calling |*| and |.*| The same is for |^| |.^| etc. Change * |*| to |.*| * |/| to...

6 years ago | 0

Using ifft to get the Fourier Coefficient
N=256; X=2*N; L=2*pi; x=linspace(-pi,pi,X); c=0; k = 2*pi*((1:2*N)-N-1)/L; % vectorised y = sin(x); % don't understand w...

6 years ago | 0

Exporting table to excel
You don't have to join tables before exporting them. You can just create spreadsheet and then add other data in other sheets or ...

6 years ago | 2

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Dividing matrix in four parts
A = zeros(210,3); %example split = [40 60 30 80]; A_split = mat2cell(A,split); [B, C, D, E] = A_split{:}; doc mat2...

6 years ago | 0

# If you have to use loop, <http://nl.mathworks.com/help/matlab/matlab_prog/preallocating-arrays.html preallocate> variable _RMS...

6 years ago | 1

How to rank a vector with repeats without MATLAB unique?
Do you want to replicate following behaviour? [~, ~, rank] = unique(data); rank = rank.'; There are thousands of ways...

6 years ago | 0

1. It seems your function rocket.m represents system of equations dH₁ = H₂ dH₂ = aH₁² + 127530 Verify, if it's what y...

6 years ago | 0

Problem with categorical arrays
(Copied from comments as suggested.) You are trying to make categorical array from a variable of mixed data types. categ...

6 years ago | 1

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I have a n X 2 matrix, but I want remove the points with a distance smaller than a threshold. And the data is random, which means the data position may be very far in the matrix but their distance is very close. Can anyone help me?
dataOut = uniquetol(dataIn, tolerance, 'ByRows', true); Above code should be a good starting point. In this case it would b...

6 years ago | 0

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Is there a way for breaking a loop iteration, if it takes to long?
One of the simplest ways for time control is to use tic and toc time0 = tic; timeLimit = 60*60*1; % 1 hour == 3600 secon...

6 years ago | 1

Why are title and x/y lable not listed in Children property of axes?
The answer is that those aren't axes children. Here is documentation page that mention it: <https://nl.mathworks.com/help/matla...

6 years ago | 0

Rotate Meshgrid 45 Degrees
theta = 45; x2 = x*cosd(theta) - y*sind(theta); y2 = x*sind(theta) + y*cosd(theta);

6 years ago | 0

Question

Circshift bug for sparse logical.
Hello, does anybody know if it has been reported? Circshift seems to shift sparse logicals properly, but changes trues to fal...

7 years ago | 0 answers | 3

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How do i get index of a closest value from an array?
Try something like this: divisor = 900; how_close_is = abs(mod(a+divisor/2,divisor)-divisor/2); index_chunk=find(how_...

7 years ago | 0