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

function reconstructionMATLAB

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.

Best Answer

Working with your Excel file was something of an adventure!
I assume ‘n’ are nanoseconds and ‘u’ are microseconds. The plot works correctly with those assumptions.
Try this: 
[D,S] = xlsread('1.csv');
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.
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