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TransceiverUHD: Add receive overpower alerting 

Detect when the sample input level reaches 94% of full scale input,
which equates to amplitude of 120 for 8-bit samples post-conversion,
and log the event with ALERT level.

Signed-off-by: Tom Tsou <tom@tsou.cc>
This commit is contained in:
Tom Tsou 2015-01-23 19:03:41 -08:00 committed by Michael Iedema
parent 6cb7498e64
commit d0bae40d8b
1 changed files with 16 additions and 0 deletions
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16
TransceiverUHD/RadioInterface.cpp
View File

@ -61,6 +61,9 @@ extern "C" {
/* Receive scaling factor for 16 to 8 bits */
#define CONVERT_RX_SCALE (128.0 / 32768.0)
/* Clipping detection threshold */
#define CLIP_THRESH 120.0f
UMTS::Time VectorQueue::nextTime() const
{
UMTS::Time retVal;
@ -302,6 +305,16 @@ bool RadioInterface::pushBuffer(void)
return true;
}
static int detectClipping(float *buf, int len, float thresh)
{
for (int i = 0; i < len; i++) {
if (fabsf(buf[i]) > thresh)
return 1;
}
return 0;
}
bool RadioInterface::pullBuffer(void)
{
bool localUnderrun;
@ -324,6 +337,9 @@ bool RadioInterface::pullBuffer(void)
float *convert_out = (float *) (outerRecvBuffer->begin() + dnsampler->len());
convert_short_float(convert_out, convert_in, CONVERT_RX_SCALE, outchunk * 2);
if (detectClipping(convert_out, outchunk * 2, CLIP_THRESH)) {
LOG(ALERT) << "Overpower detected on receive input";
}
underrun |= localUnderrun;
readTimestamp += outchunk;