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import changes for hsdaohSDR

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input is 8/10 bit IQ samples from
https://github.com/steve-m/hsdaoh-fpga/tree/sdr

output is IQ as float with DC offset removal
This commit is contained in:
Steve Markgraf 2024-05-31 00:29:30 +02:00
parent c6fbfa398a
commit 2a49b18662
1 changed files with 100 additions and 2 deletions
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102
src/libhsdaoh.c
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@ -90,6 +90,10 @@ struct hsdaoh_dev {
unsigned int width, height, fps;
/* for IQ DC offset removal */
float avg_real;
float avg_img;
/* status */
int dev_lost;
int driver_active;
@ -549,6 +553,95 @@ int hsdaoh_close(hsdaoh_dev_t *dev)
return 0;
}
/* IQ DC offset removal in the style of GNURadio, although with constant
* tracking by using only 1/128 of the samples */
void hsdaoh_remove_dc_offset(hsdaoh_dev_t *dev, float *in, size_t length)
{
unsigned int i;
float ratio = 1e-05f;
float avg_real = dev->avg_real;
float avg_img = dev->avg_img;
// do some sync for tracking
for (i = 0; i < length/128; i+=2) {
avg_real = ratio * (in[i] - avg_real) + avg_real;
avg_img = ratio * (in[i+1] - avg_img) + avg_img;
}
dev->avg_real = avg_real;
dev->avg_img = avg_img;
for (i = 0; i < length; i+=2) {
in[i] -= avg_real;
in[i+1] -= avg_img;
}
}
int hsdaoh_handle_payload_10bit(hsdaoh_dev_t *dev, uint16_t *buf, size_t length)
{
unsigned int i, j = 0;
uint16_t *samps = malloc(sizeof(uint16_t) * dev->width * dev->height * 2);
float *floats = malloc(sizeof(float) * dev->width * dev->height * 2);
if (!samps || !floats)
return -ENOMEM;
/* extract packed 10 bit samples, 4 words are the 8 bit IQ samples,
* and the 5th word contains the packed lower two bits of each I and Q sample */
for (i = 0; i < length; i += 5) {
uint16_t lsbs = buf[i+4];
samps[j++] = ((buf[i+0] & 0xff00) >> 6) | ((lsbs >> 0) & 3);
samps[j++] = ((buf[i+0] & 0x00ff) << 2) | ((lsbs >> 2) & 3);
samps[j++] = ((buf[i+1] & 0xff00) >> 6) | ((lsbs >> 4) & 3);
samps[j++] = ((buf[i+1] & 0x00ff) << 2) | ((lsbs >> 6) & 3);
samps[j++] = ((buf[i+2] & 0xff00) >> 6) | ((lsbs >> 8) & 3);
samps[j++] = ((buf[i+2] & 0x00ff) << 2) | ((lsbs >> 10) & 3);
samps[j++] = ((buf[i+3] & 0xff00) >> 6) | ((lsbs >> 12) & 3);
samps[j++] = ((buf[i+3] & 0x00ff) << 2) | ((lsbs >> 14) & 3);
}
for (i = 0; i < j; i += 2) {
floats[i] = (samps[i] - 511.5) * (1/512.0);
floats[i+1] = (samps[i+1] - 511.5) * (1/512.0);
}
hsdaoh_remove_dc_offset(dev, floats, j);
if (dev->cb)
dev->cb((uint8_t *)floats, j * sizeof(float), dev->cb_ctx);
free(floats);
free(samps);
return 0;
}
int hsdaoh_handle_payload_8bit(hsdaoh_dev_t *dev, uint16_t *buf, size_t length)
{
float *floats = malloc(sizeof(float) * dev->width * dev->height * 2);
if (!floats)
return -ENOMEM;
for (unsigned int i = 0; i < length * 2; i += 2) {
float sample_i = (buf[i/2] >> 8) & 0xff;
float sample_q = (buf[i/2] & 0xff);
floats[i] = (sample_i - 127.4) * (1/128.0);
floats[i+1] = (sample_q - 127.4) * (1/128.0);
}
hsdaoh_remove_dc_offset(dev, floats, length * 2);
if (dev->cb)
dev->cb((uint8_t *)floats, length * 2 * sizeof(float), dev->cb_ctx);
free(floats);
return 0;
}
/* callback for idle/filler data */
inline int hsdaoh_check_idle_cnt(hsdaoh_dev_t *dev, uint16_t *buf, size_t length)
{
@ -626,8 +719,13 @@ void hsdaoh_process_frame(hsdaoh_dev_t *dev, uint8_t *data, int size)
frame_payload_bytes += payload_len*2;
}
if (dev->cb)
dev->cb(data, frame_payload_bytes, dev->cb_ctx);
if (meta.pack_state & 0x10)
hsdaoh_handle_payload_10bit(dev, (uint16_t *)data, frame_payload_bytes/sizeof(uint16_t));
else
hsdaoh_handle_payload_8bit(dev, (uint16_t *)data, frame_payload_bytes/sizeof(uint16_t));
// if (dev->cb)
// dev->cb(data, frame_payload_bytes, dev->cb_ctx);
if (frame_errors && dev->stream_synced) {
fprintf(stderr,"%d idle counter errors, %d frames since last error\n", frame_errors, dev->frames_since_error);