58 lines
1.8 KiB
C
58 lines
1.8 KiB
C
/*
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* Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The OpenAirInterface Software Alliance licenses this file to You under
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* the OAI Public License, Version 1.1 (the "License"); you may not use this file
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* except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.openairinterface.org/?page_id=698
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*-------------------------------------------------------------------------------
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* For more information about the OpenAirInterface (OAI) Software Alliance:
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* contact@openairinterface.org
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*/
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/******************************
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* file: angle.c
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* purpose: compute the angle of a 8 bit complex number
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* author: florian.kaltenberger@eurecom.fr
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* date: 22.9.2009
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*******************************/
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#include "costable.h"
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#include "defs.h"
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unsigned int angle(c16_t perror)
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{
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int a;
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// a = atan(perror.i/perror.r);
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//since perror is supposed to be on the unit circle, we can also compute a by
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if (perror.i>=0) {
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if (perror.r>=0)
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a = acostable[min(perror.r,255)];
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else
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a = 32768-acostable[min(-perror.r,255)];
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//a = asin(perror.i);
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} else {
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if (perror.r>=0)
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a = 65536-acostable[min(perror.r,255)];
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else
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a = 32768+acostable[min(-perror.r,255)];
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//a = 2*PI-asin(perror.i);
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}
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return a;
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}
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