API Documentation

WXG-DAQ-2480 has a built-in IQ demodulation function for balanced detector DAS system, which supports both single-channel IQ demodulation and dual-channel IQ demodulation. When uploading raw data or single channel demodulation function is used, the maximum number of points per frame (the number of points captured by a single trigger pulse) can support 130048 points, i.e., the length of the optical fiber can reach up to 130048*0.4m=52.019km under the sampling rate of 250M (0.4m spatial resolution);

int DasCardOpen()
/****************************************************************/ 
Open the device, called when the program starts, until the program exit, the whole process only need to call once, and DasCardClose pair call.
Function Parameters 
None
Function return value: 
Success, return 0 
Failure, return -1
/****************************************************************/

void  DasCardClose();
/****************************************************************/  Function Description:
Close the device, called when the program exits, the whole process only need to be called once, called in pairs with DasCardOpen.
 Function parameters:
None
Function return value:
None
/****************************************************************/

int DasCardStart()
/****************************************************************/ Function Description:
Start to collect data, call this function after the collection will start to collect data according to the set parameters, and will write the data into the cache for the user to read, this function is called after all the parameters have been set, and DasCardStop is called in pairs.
function parameters:
None
The function returns a value:
Success, return 0 
Failure, return -1
/****************************************************************/

int DasCardStop()
/****************************************************************/ 
Function Description:
Stop collecting data, the function will stop collecting data after the function is called, and DasCardStart function is called in pairs.
Function parameters:
None
Function return value:
Success, return 0 
Failure, return -1
/****************************************************************/

int DasCardSetPulseWidth(int width)
/****************************************************************/
Function Description:
Set pulse width, unit ns, valid when internal trigger is used, trig-out will output trigger pulse with set width.
Function parameter:
width, output trigger pulse width, unit ns, step by 4ns.
Function return value:
Success, return 0
Failure, return -1
/****************************************************************/

int DasCardSetPulseFrq(int frq)
/****************************************************************/
Function Description:
Set the trigger pulse frequency, valid when internal trigger is used, trig-out will output the trigger pulse of the set frequency.
Function parameter:
frq.
Trigger pulse output frequency.
Function return value:
Success, return 0
Failure, return -1
/****************************************************************/

int DasCardSetSampleNum(int num)
/****************************************************************/ 
Function Description:
Set the number of sampling points, i.e. the number of data points sampled by one pulse trigger.
Function parameter:
num, the number of trigger sampling points.
Function return value:
Success, return 0
Failure, return -1
/****************************************************************/

int DasCardSetPulseNum(int num)
/****************************************************************/ 
Function Description:
Set the number of data segments to be written to the cache at one time, each time the pulse trigger samples a segment of data, and after sampling num segments of data, the data will be written to the cache at one time for the user to read, and it is recommended that the user reads the data in accordance with the num segments of data at one time.
Function parameters:
num, the number of data segments to be written to the cache at one time, recommended value is 10-100.
Function return value:
Success, return 0 
Failure, return -1
/****************************************************************/

int DasCardSetDataSel(int sel)
/****************************************************************/ 
Function Description:
The digital down-conversion function has already been done on the board, so that the collected data can be demodulated by digital I/Q. The sel parameter is used to select the corresponding data type in the read demodulation algorithm.