From 351fd7670649cafd5344cf6fc746f63729df97cb Mon Sep 17 00:00:00 2001 From: Alexander Chemeris Date: Sun, 24 May 2015 20:16:51 -0400 Subject: sigProcLib: Fix burst start phase. R&S CMD57 complains about the start phase of bursts, particularly it shows -15 to -30 deg of error for the bit 0.5 position (start tail bit). This patch makes it happy. ETSI TS 145 004 section 2.2 describes this: "Before the first bit of the bursts as defined in 3GPP TS 45.002 enters the modulator, the modulator has an internal state as if a modulating bit stream consisting of consecutive ones (di = 1) had entered the differential encoder." Signed-off-by: Tom Tsou --- Transceiver52M/sigProcLib.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Transceiver52M/sigProcLib.cpp b/Transceiver52M/sigProcLib.cpp index 4501a13..9d8410b 100644 --- a/Transceiver52M/sigProcLib.cpp +++ b/Transceiver52M/sigProcLib.cpp @@ -726,7 +726,7 @@ static signalVector *modulateBurstLaurent(const BitVector &bits, c1_itr = c1_burst->begin(); /* Padded differential start bits */ - *c0_itr = 2.0 * (0x00 & 0x01) - 1.0; + *c0_itr = 2.0 * (0x01 & 0x01) - 1.0; c0_itr += sps; /* Main burst bits */ -- cgit v1.2.3