# How to reduce the sample rate of a over sampled signal? (How to connect data to lines and sample?)

12 views (last 30 days)
Minghao Dong on 10 Aug 2019
Commented: Star Strider on 11 Aug 2019
Hi Team,
I have a set of date, for example, sampled at 491.52-MHz. However, I want them to be sampled at 300-MHz using matlab processing. I am thinking I should use the original 491.52-MHz sampled data to reconstruct the original signal and then sample the new reconstructed signal with 300-MHz sample rate. Can anyone help me how to achieve it
The 491.52-MHz data is in attachment.

Star Strider on 10 Aug 2019
I assume ‘n’ are nanoseconds and ‘u’ are microseconds. The plot works correctly with those assumptions.
Try this:
t = cellfun(@(x)sscanf(x, '%f'), S(3:end,3), 'Uni',0); % Recover Time Vector
nu = regexp(S(:,3), '[un]', 'match'); % Recover ‘n’ & ‘u’
nv = strcmp([nu{:}],'n'); % Logical Vector: ‘n’
uv = strcmp([nu{:}],'u'); % Logical Vector: ‘u’
mult = [[0, nv(nv)]*1E-9, uv(uv)*1E-6]; % Create Multiplier Vector From ‘n’ and ‘u’
t = cell2mat([D(1,1); t]); % Concatenate With Initial ‘t’
tv = t .* mult(:); % Reconstruct ‘t’ With Multipliers
s = D(:,2); % Signal Vector
ts = sortrows([tv, s]); % Reconstructed Time & Waveform Matrix
% Ts = mean(diff(ts(:,1))), Tsd = std(diff(ts(:,1))), Fs = 1/Ts % Original Values
Fs = 300E+6; % Desired Resampling Frequency: 300MHz
[sr, tr] = resample(ts(:,2), ts(:,1), Fs); % Resample Using Original ‘t’ & ‘s’
figure
plot(ts(:,1), ts(:,2))
grid
title('Original Signal')
figure
plot(tr, sr)
grid
title('Resampled Signal')
That should give you the resultl you want.
##### 2 CommentsShowHide 1 older comment
Star Strider on 11 Aug 2019
As always, my pleasure!
That file was a challenge!

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!