bladerf: Removed sign extension and masking of samples

This is no longer required as of FPGA v0.0.1, and has been removed to
remove some unnecessary computation on samples.
wip-signat
Jon Szymaniak 9 years ago committed by Dimitri Stolnikov
parent 4a0d74f059
commit 03c387bcda
  1. 27
      lib/bladerf/bladerf_source_c.cc

@ -83,6 +83,7 @@ bladerf_source_c::bladerf_source_c (const std::string &args)
int ret;
size_t fifo_size;
std::string device_name;
struct bladerf_version fpga_version;
dict_t dict = params_to_dict(args);
@ -139,6 +140,19 @@ bladerf_source_c::bladerf_source_c (const std::string &args)
/* Set the range of VGA2 VGA2GAIN[4:0], not recommended to be used above 30dB */
_vga2_range = osmosdr::gain_range_t( 0, 60, 3 );
/* Warn user about using an old FPGA version, as we no longer strip off the
* markers that were pressent in the pre-v0.0.1 FPGA */
if (bladerf_fpga_version( _dev.get(), &fpga_version ) != 0) {
std::cerr << _pfx << "Failed to get FPGA version" << std::endl;
} else if ( fpga_version.major <= 0 &&
fpga_version.minor <= 0 &&
fpga_version.patch < 1 ) {
std::cerr << _pfx << "Warning: FPGA version v0.0.1 or later is required. "
<< "Using an earlier FPGA version will result in misinterpeted samples. "
<< std::endl;
}
}
/*
@ -186,6 +200,7 @@ void *bladerf_source_c::stream_task( void *samples, size_t num_samples )
size_t i, n_avail, to_copy;
int16_t *sample = (int16_t *)samples;
void *ret;
const float scaling = 1.0f / 2048.0f;
ret = _buffers[_buf_index];
_buf_index = (_buf_index + 1) % _num_buffers;
@ -196,17 +211,9 @@ void *bladerf_source_c::stream_task( void *samples, size_t num_samples )
to_copy = (n_avail < num_samples ? n_avail : num_samples);
for(i = 0; i < to_copy; i++ ) {
/* Mask valid bits only */
*(sample) &= 0xfff;
*(sample+1) &= 0xfff;
/* Sign extend the 12-bit IQ values, if needed */
if( (*sample) & 0x800 ) *(sample) |= 0xf000;
if( *(sample+1) & 0x800 ) *(sample+1) |= 0xf000;
/* Push sample to the fifo */
_fifo->push_back( gr_complex( *sample * (1.0f/2048.0f),
*(sample+1) * (1.0f/2048.0f) ) );
_fifo->push_back( gr_complex( *sample * scaling,
*(sample+1) * scaling) );
/* offset to the next I+Q sample */
sample += 2;

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