how to convert absolute time to real time and calculate the sampling rate

Hello to all...In this file, I have the absolute time and date and day of data registration. Now I want to get the real time and calculate the sampling rate from the difference of the frames with each other and their inverse. I have a problem with the MATLAB code. In the first step, I don't know how to calculate the real time and do the next steps? Help me please. Thanks a lot

Answer 1

[Les Beckham]

load metaData_Depth
fn = @(s) datetime(s.AbsTime);
dt = arrayfun(fn, metaData_Depth)

dt = 150×1 datetime array
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delta_t = seconds(diff(dt))

delta_t = 149×1

0.0209 0.0315 0.0631 0.1337 0.1658 2.5103 0.0901 0.1112 0.2360 0.0295

max(delta_t)

ans = 2.5103

min(delta_t)

ans = 0.0162

numel(unique(delta_t))

ans = 149

mean(delta_t)

ans = 0.0939

std(delta_t)

ans = 0.2075

plot(delta_t, '.')
grid on

So, every single sample has a different duration of time between it and the next sample. Thus, it isn't going to make much sense to calculate a sample rate for this data.

[NGR MNFD]

tnx very much,It was great. Thank you very much for your explanation

[Les Beckham]

You are quite welcome.

[NGR MNFD]

Something went wrong here. I just need to set delta_t so that it calculates the time as the difference of each row from the first row, not two rows in a row.

[NGR MNFD]

How should we enter the MATLAB code for this section (delta_t = seconds(diff(dt)))?

[NGR MNFD]

In other words, start the time vector from the first row (0.0209) and subtract the rest of the rows from the first row. How do we calculate delta _t with this calculator? I don't know, do you understand what I mean?

[Voss]

load metaData_Depth

C = num2cell(vertcat(metaData_Depth.AbsTime),1);
dt = datetime(C{:})

dt = 150×1 datetime array
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delta_t = dt - dt(1)

delta_t = 150×1 duration array
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[NGR MNFD]

tnx very much.