Add time column to Matlab .MAT file export

#1 · 26/10/2021, 13:47

Hello,

When exporting to Matlab .MAT file from the RTSA File Reader block, I get a mat file with IQ data only. But there is no time column. See below for my workspace after loading the file into matlab. Would it be possible to have a time variable added to the .mat file.

The CSV file export has a time column (and maybe other file format), but not the .mat file. The IQ data is single precision, so I guess the time would also be single precision 7 Decimal Places. This would be 100ns resolution. Is that enough?

>> load('xxx.mat')
>> whos
Name Size Bytes Class Attributes

IQ 2x284167060 2273336480 single

Best regards,

Brian

#2 · 28/10/2021, 13:09

No problem but since Matlab is a binary, and we are no cracks in the usage of Matlab, we simply need the information how to add/integrate it to the data format:

if (mFirstPacket)
		{
			struct MatHeader
			{
				char		mName[116];
				quint32		mSubSysLow, mSubSysHigh;
				quint32		mFlags;

				quint32		mMatTag;
				quint32		mMatSize;

				quint32		mMatFlagsTag;
				quint32		mMatFlagsSize;
				quint32		mMatFlagsLow, mMatFlagsHigh;

				quint32		mMatDimTag;
				quint32		mMatDimSize;
				qint32		mMatDims[2];

				quint16		mMatNameTag, mMatNameSize;
				char		mMatName[4];

				quint32		mMatDataTag;
				quint32		mMatDataSize;
			}	header = {0};

			memset(header.mName, ' ', 116);
			strcpy(header.mName, "RTSA");
			header.mSubSysLow = header.mSubSysHigh = 0;
			header.mFlags = 0x4d490100;

			header.mMatTag = 0x0000000e;
			header.mMatSize = packet->mType->mSampleSize * sizeof(float) * mTotalSamples + 12 * 4;

			header.mMatFlagsTag = 0x00000006;
			header.mMatFlagsSize = 8;
			header.mMatFlagsLow = 0x00000007;
			header.mMatFlagsHigh = 0x00000000;

			header.mMatDimTag = 0x00000005;
			header.mMatDimSize = 8;
			header.mMatDims[0] = packet->mType->mSampleSize;
			header.mMatDims[1] = mTotalSamples;

			header.mMatNameTag = 0x0001;
			header.mMatNameSize = 2;

			if (packet->mType->mPayloadType == DSPT_IQ)
				strcpy(header.mMatName, "IQ");
			else
				strcpy(header.mMatName, "SP");

			header.mMatDataTag = 0x00000007;
			header.mMatDataSize = packet->mType->mSampleSize * sizeof(float) * mTotalSamples;

			mFile.write((char *)&header, sizeof(MatHeader));
		}

		size_t	sampleSize = packet->SampleDataSize();
		for(quint32 i=startIndex; i<endIndex; i++)
		{
			mFile.write((char *)(packet->SampleDataPtr(i)), sampleSize);
		}