Wavecom W61PC V7.5.0 - Manual (Page 319)

WAVECOM Decoder W61PC/LAN Manual V7.5 WAVECOM Data Formats  309
To the default file header with 64 bytes additional a block of 48 bytes is added.
The additional block contains display parameter used by the WAVECOM GUI for displaying the stored data
correctly.
NOTE: the following struct type could be used to extract the data header.
struct SonagramData
{
long lDocSizeX;
long lDocSizeY;
double dCursorA;
double dCursorB;
long lBandwidth;
long lTranslation;
long lLowFrequencyLimit;
long lHighFrequencyLimit;
short sLowMagnitudeLimit;
short sHighMagnitudeLimit;
BOOL boVideoFilterOn;
};
Data
This ‘FileType’ uses the data structure described in chapter “ Data Structures ” on page 304 to store the da-
ta.
The stored sonagram data has the following structure:
 FFT Samples: the first 4096 bytes of the stored data contain the 2048 sample values for the FFT.
 Time: the last 16 bite of the stored data contains the system time timestamp value of the received
data( the additional timestamp is necessary because the default timestamp in the data header
does not support milliseconds ). The TIME value is the the number of seconds elapsed since mid-
night (00:00:00), January 1, 1970, coordinated universal time, according to the system clock.
The data for the ‘Sonagram’ file types occupies 4112 bytes inside a data package after the data header.
A data package in the .WDA file contains the data points of one FFT sample and its timestamp value. The
FFT sample data points are stored in short values(2-bit type), that is 2 Bytes in the .WDA file contains the
value of one FFT sample data point.
NOTE: the following struct type could be used to extract the data.
4096 Bytes 16 Bytes
FFTSamples Time
12 Bytes n Bytes
DataHeader Data