From fa3a787ccbb250d929ebf78993047dd05e8765cb Mon Sep 17 00:00:00 2001 From: Thomas Tsou Date: Thu, 17 Oct 2013 21:23:34 -0400 Subject: Transceiver52M: Update noise measurement calculation Previous removal of the energy detector requirement broke the noise level calculation loop. The previous adaptive approach was finicky - noticably at high gain levels. Since we no longer use the energy threshold for primary burst gating, we can return to a simpler world. In the new approach, we compute a running average of energy levels and track them with a noise vector. A timeslot that passes the correlator threshold is a valid burst. These are not used in the noise calculation. Everything else is considered noise and used to compute the noise level with respect to full scale input level, which for almost all supported devices is 2^15. Signed-off-by: Thomas Tsou --- Transceiver52M/Transceiver.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'Transceiver52M/Transceiver.h') diff --git a/Transceiver52M/Transceiver.h b/Transceiver52M/Transceiver.h index d243214..c0ada1d 100644 --- a/Transceiver52M/Transceiver.h +++ b/Transceiver52M/Transceiver.h @@ -97,6 +97,8 @@ private: LOOPBACK ///< similar go VII, used in loopback testing } ChannelCombination; + float mNoiseLev; ///< Average noise level + noiseVector mNoises; ///< Vector holding running noise measurements /** unmodulate a modulated burst */ #ifdef TRANSMIT_LOGGING @@ -134,8 +136,6 @@ private: double mRxFreq; ///< the receive frequency int mPower; ///< the transmit power in dB unsigned mTSC; ///< the midamble sequence code - double mEnergyThreshold; ///< threshold to determine if received data is potentially a GSM burst - GSM::Time prevFalseDetectionTime; ///< last timestamp of a false energy detection int fillerModulus[8]; ///< modulus values of all timeslots, in frames signalVector *fillerTable[102][8]; ///< table of modulated filler waveforms for all timeslots unsigned mMaxExpectedDelay; ///< maximum expected time-of-arrival offset in GSM symbols -- cgit v1.2.3