1G DAQ data acquisition card output data format

Reading the API documentation of the capture card, we can see the read interface as follows.

int pcie7820_set_upload_data_param(unsigned int upload_ch_num,unsigned int upload_data_src,unsigned int upload_data_rate)

function description：

Set up the board upload data parameters. Digital downconversion has been done on the board to perform digital I/Q demodulation of the collected data. The upload_ch_num parameter and upload_data_src are used together to select where in the demodulation algorithm to read the data.

Digital Quadrature Demodulation Process

function parameter：

upload_ch_num ：Set the number of channels to upload;

1 - upload one channel of data; 2 - upload two channels of data; 4 - upload four channels of data;

upload_data_src：Upload data source selection；

0 - upload raw acquisition data; 2 - upload IQ data; 3 - upload phase and magnitude data;

upload_data_rate：Sets the upload data rate;

1---1GSps；2---500MSps；4---250MSps；8---125MSps；12---83.333MSps；

16---62.5MSps；20---50MSps；24---41.66MSps；28---35.714MSps；

32---31.25MSps；

The function returns the value:

Success, 0
Failure, -1

The data read by the pcie7820_read_data function should be parsed according to the following table：

ch0_raw_data---ch1_raw_data---I0---Q0---I1----Q1--- arctan(Q0/I0)--- arctan(Q1/I1)，These 8 types of data need to be parsed as 16-bit signed data (short).；√(I02+Q02)---√(I12+Q12)，These two types of data need to be parsed as 16-bit unsigned short numbers.

The arctan phase value read up is a fixed point number, and its correspondence with π is: 25735 - positive π, -25735 - negative π.