fir-wb.c

Reference Implementation of G.711 standard and other voice codecs

/*                                                               10.Feb.2005 v2.2
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                   ========================================
                    ITU-T - USER'S GROUP ON SOFTWARE TOOLS
                   ========================================

       =============================================================
       COPYRIGHT NOTE: This source code, and all of its derivations,
       is subject to the "ITU-T General Public License". Please have
       it  read  in    the  distribution  disk,   or  in  the  ITU-T
       Recommendation G.191 on "SOFTWARE TOOLS FOR SPEECH AND  AUDIO
       CODING STANDARDS".
       =============================================================

MODULE:         FIRFLT, HIGH QUALITY FIR UP/DOWN-SAMPLING FILTER
                Sub-unit: 
		Wideband speech filtering functions:
		- P.341 send-part characteristic
		- 50 Hz to 5 kHz bandpass filter (for wideband qual.tests)
		- 100Hz to 5kHz bandpass filter  (for wideband qual.tests)
		- 50 Hz to 14kHz bandpass filter (for a sampling frequency of 32kHz)

ORIGINAL BY:
                Simao Ferraz de Campos Neto (C code)
		Comsat Laboratories             Tel:    [phone]
		22300 Comsat Drive              Fax:    [phone]
		Clarksburg MD 20871 - USA       E-mail: [e-mail]

		Rosario Drogo de Iacovo (filter coefficients)
		CSELT
		Audio Coding and Transmission Quality  Tel: [phone]
		Via G.Reiss Romoli, 274                Fax: [phone]
		10148 Torino - ITALY     
		Email: [e-mail]

DESCRIPTION:
        This file contains procedures for FIR filtering according to the 
	mask in ITU-T Recommendation P.341 for wideband telephones.

FUNCTIONS:
  Global (have prototype in firflt.h)
  Local (should be used only here -- prototypes only in this file)

  Global (have prototype in firflt.h)
         = p341_16khz_init(): initialize P.341 send-part weighting filter
		 = bp5k_16khz_init(): initialize 5kHz bandpass filter
		 = bp100_5k_16khz_init(): initialize 100Hz-5kHz bandpass filter
		 = bp14k_32khz_init(): initialize 14kHz bandpass filter

  Local (should be used only here -- prototypes only in this file)
         = fill_p341_16khz(...): filling filter coefficients into
                                 array for P.341 send-part weighting
         = fill_bp5k_16khz(...): idem, for 5kHz bandpass filtering
         = fill_bp100_5k_16khz(...): idem, for 100Hz-5kHz bandpass filtering
         = fill_bp14k_32khz(...): idem, for 14kHz bandpass filtering


HISTORY:
    31.Jul.1995 v1.0 First beta-version <[e-mail]>
    13.May.1997 v2.0 Added 50-5000 Hz bandpass filter
    28.Mar.2000 v2.1 Added type casting to float in fill_p341_16khz() 
                     and fill_bp5k_16khz() to eliminate compilation warnings in 
                     MS Visual C compiler <[e-mail]>
    10.Feb.2005 v2.2 Added 50-14000 Hz bandpass filter
					 Added 100-5000kHz bandpass filter
						Cyril Guillaum