Rank: 147 based on 532 downloads (last 30 days) and 15 files submitted
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M. A. Hopcroft

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Professional Interests:
sensors, MEMS, resonators, energy systems

 

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Files Posted by M. A. View all
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(last 30 days)
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18 Mar 2014 Screenshot allan Calculates standard Allan Deviation (ADEV) of a time domain signal. Author: M. A. Hopcroft statistics, probability, allan deviation, allan variance, frequency stability, stability 102 10
  • 4.6
4.6 | 5 ratings
18 Mar 2014 Screenshot allan_modified allan_modified.m calculates the modified Allan deviation (MDEV) of a time domain signal. Author: M. A. Hopcroft adev, mdev, frequency stability, allan variance, probability, statistics 26 2
  • 3.0
3.0 | 1 rating
18 Mar 2014 Screenshot allan_overlap Calculates overlapping Allan Deviation (ADEV) of a time domain signal. Author: M. A. Hopcroft adev, statistics, frequency stability, allan variance 34 2
  • 5.0
5.0 | 2 ratings
10 Dec 2013 Screenshot labJack U6 class LABJACKU6 is a class file for working with a LabJack U6 data acquisition device on Linux or OS X. Author: M. A. Hopcroft instrument control, data acquisition, instrument driver, daq 22 0
10 Oct 2013 Screenshot rd scripts A collection of scripts which load the data from contact surface profilometers Author: M. A. Hopcroft hardware driver, surface profilometer ... 22 1
  • 5.0
5.0 | 1 rating
Comments and Ratings by M. A. View all
Updated File Comments Rating
27 Sep 2013 allan Calculates standard Allan Deviation (ADEV) of a time domain signal. Author: M. A. Hopcroft

@Mauricio: yes, you are correct. The values returned by the function are ADEV values and you can square them to get AVAR values.

24 Sep 2013 LVM file import Imports LabView .lvm data files into MATLAB Author: M. A. Hopcroft

I have uploaded a new version with more fixes for comma-separated files and better overall performance. Thanks to @die-kenny for bug reports and testing and S. Danylenko for suggestions.

16 Jan 2013 allan Calculates standard Allan Deviation (ADEV) of a time domain signal. Author: M. A. Hopcroft

I'll have a look at it if you send me an email with some more details.

31 May 2012 LVM file import Imports LabView .lvm data files into MATLAB Author: M. A. Hopcroft

@Omar: good point. LabView creates an empty column with the label "X_Value" even if there is no X data in the file. The latest version of lvm_import ignores the label if there is no X data in the file.

19 Mar 2012 LVM file import Imports LabView .lvm data files into MATLAB Author: M. A. Hopcroft

Thank you for all the feedback. There was a bug in lvm_import related to LVM files that use a comma as a decimal separator instead of a period, so that in files that use a comma, the data was returned as strings instead of numbers, as @Pedram and @Andreas experienced. That has been fixed in the latest version of lvm_import.

Comments and Ratings on M. A.'s Files View all
Updated File Comment by Comments Rating
27 Sep 2013 allan Calculates standard Allan Deviation (ADEV) of a time domain signal. Author: M. A. Hopcroft Hopcroft, M. A.

@Mauricio: yes, you are correct. The values returned by the function are ADEV values and you can square them to get AVAR values.

26 Sep 2013 allan Calculates standard Allan Deviation (ADEV) of a time domain signal. Author: M. A. Hopcroft Mauricio

Hi,
using this file produces ADEV plot, now
if I try to find the Angle Random Walk (ARW) which is found from AVAR plot at tau=1, would I just have to square the ADEV value at tau=1, or not?
thanks!

24 Sep 2013 LVM file import Imports LabView .lvm data files into MATLAB Author: M. A. Hopcroft Hopcroft, M. A.

I have uploaded a new version with more fixes for comma-separated files and better overall performance. Thanks to @die-kenny for bug reports and testing and S. Danylenko for suggestions.

16 Jul 2013 LVM file import Imports LabView .lvm data files into MATLAB Author: M. A. Hopcroft Giacomo

I use this code for my job: very useful, thanks a lot!

@ Sviatoslav Danylenko: I tried your modifications: very effective!

29 Jun 2013 LVM file import Imports LabView .lvm data files into MATLAB Author: M. A. Hopcroft Danylenko, Sviatoslav

Hello, Hopcroft

If you want, you can increase speed of reading lvm files with non-dot decimal separator. It will be quick almost as reading of dot separated lvm files (speed difference is about 0.01-0.03 sec).

You need to replace this lines:
% handle case of not using periods (aka "dot" or ".") for decimal point separators
% (LVM version 2.0+)
if ~strcmp(data.Decimal_Separator,'.')
...
end

with this:

if ~strcmp(data.Decimal_Separator,'.')
if verbose >= 2, fprintf(1,'\n (using decimal separator "%s")\n',data.Decimal_Separator); end

valuesSource = fileread(filename);
valuesSource = strrep(valuesSource(ftell(fid):end), data.Decimal_Separator,'.');
else
valuesSource = fid;
end
% create a format string for reading data as numbers
fs = '%f'; for i=2:numdatacols, fs = [fs ' %f']; end %#ok<AGROW>
% add one more column for the comment field
fs = [fs ' %s']; %#ok<AGROW>
% read the data from file
[rawdata,position] = textscan(valuesSource,fs,'delimiter',text_delimiter);
% save first row comment as The Comment for this segment
data.(fieldnm).Comment = rawdata{size(rawdata,2)}{1};

if ~strcmp(data.Decimal_Separator,'.')
% fixing position in file
% we substituting one char more, that we actually need
% that extra char we will read at the next line. we use this to
% trigger eof flag for function feof()
fseek(fid, position-2, 'cof');
fscanf(fid, '%c');
end

Best Regards and Thanks for the lvm_import,
Sviatoslav

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