Hi,
I wrote a c++ program that grabs data from the USRP in an infinite loop
and does nothing with it. It overruns. Can anyone help me figure out
why?
This runs on a 2.4GHz computer that isn’t doing anything else. I’m
sampling the A and B channel of a BasicRX at 4MHz with shorts. CPU runs
about 15%. I’ve tried many different values for NumBytes. Profile
results show nothing abnormal. This is driving me nuts!
Thank you,
Chris
#include <usrp_standard.h>
#include
using namespace std;
static const unsigned DecimRate = 16;
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
int main(int argc, char** argv)
{
static const int UsrpNumber = 0;
const unsigned Format = usrp_standard_rx::make_format(
16, // width across usb
0, // shift
true, // want Q
false // bypass halfband
);
usrp_standard_rx* rx = usrp_standard_rx::make(UsrpNumber, DecimRate);
static const int Mux = 0x33221100;
rx->set_decim_rate(DecimRate);
static const double DdcFreq = -12000e3;
static const int NumChannels = 2;
rx->set_nchannels(NumChannels);
for(int i = 0; i < NumChannels; ++i)
{
rx->set_rx_freq(i, DdcFreq);
}
rx->set_mux(Mux);
rx->set_pga(0, 0);
rx->set_pga(1, 0);
rx->set_format(Format);
static const unsigned NumBytes = 4096;
char* Buffer = new char[NumBytes];
rx->start();
bool Overrun = false;
// Throw away first 32kB of data because it’s fouled up
// with some kind of sinc
int NumTossed = 0;
while(NumTossed < 32768)
{
NumTossed += rx->read(Buffer, NumBytes, &Overrun);
}
while(true)
{
rx->read(Buffer, NumBytes, &Overrun);
if(Overrun)
{
Overrun = false;
cerr << "Overrun\n";
}
//std::cout.write(Buffer, NumBytes);
}
rx->stop();
delete [] Buffer;
return 0;
}
