Resampling scaling truncating Matlab data file

Question

Hakan Durak 2022-6-18

回答： Karan Singh 2023-10-3

I need to perform the conditions to the data file below on the matlab. can you help me how to do that.

Data File = 2x460800

Conditions:

1.) The scaling defined in the PhysioNet .info files for each PhysioNet data file was applied to each raw data file.

2.) The data were resampled to a common rate of 128 hertz.

3.) Each data file consisting of two ECG recordings was separated into two separate data records.

4.) The data length was truncated to a common length of 65536 samples.

Answer 1

Karan Singh 2023-10-3

Hi Hakan,

I understand that you need help with performing the conditions on the data file in MATLAB. Here's a guide on how to accomplish each condition:

Scaling the data: If you have the scaling factor provided in the .info file, you can multiply each data point by the scaling factor to apply the scaling eg.

“scaled_data = raw_data * scale”.

Resampling the data to 128 Hz: MATLAB provides the resample function to resample the data. Assuming your original data is stored in the variable “raw_data” and the original sampling rate is “original_fs”, you can use the following code to resample the data to 128 Hz:

desired_fs = 128;  % Desired sampling rate 
resampled_data = resample(raw_data, desired_fs, original_fs); 

Separating the data into two separate data records: Assuming the concatenated data is stored in the variable “concatenated_data”, you can use the following code to separate them:

data_record1 = concatenated_data(1:end/2); 
data_record2 = concatenated_data(end/2+1:end);

Truncating the data length to 65536 samples: Assuming your data record is stored in the variable “data_record”, you can use the following code to truncate it:

truncated_data = data_record(1:65536);

Attached below are some documentation links that you may find helpful:

Hope this helps!

Karan Singh Khati