WO2017025107A2

WO2017025107A2 - Talker language, gender and age specific hearing device

Info

Publication number: WO2017025107A2
Application number: PCT/EG2015/000047
Authority: WO
Inventors: Taha Kais Taha AL-SHALASH
Original assignee: Al-Shalash Taha Kais Taha
Priority date: 2015-11-22
Filing date: 2015-11-22
Publication date: 2017-02-16
Also published as: WO2017025107A3

Abstract

A method of operating an audio processing device to improve a user's perception of the speech signal. The method comprising: converting by the audio processing device the input speech signal into a number of frequency bands corresponding to a perception scale, applying "band specific frequency lowering scheme" mainly on to the least important frequency bands according to the specific language phonemes formantsnumber, the talker fundamental frequency as it differs among male, female and children, the importance of each of these phonemes in speech recognition and frequency of occurrence of each phoneme in conversation.

Description

TALKER LANGUAGE, GENDER AND AGE SPECIFIC HEARING DEVICE

TECHNICAL FIELD

THE PRESENT APPLICATION RELATES TO IMPROVEMENTS IN SPEECH PERCEPTION, E.G. SPEECH INTELLIGIBILITY, IN PARTICULAR TO

IMPROVING SOUND PERCEPTION FOR A PERSON, E.G. A HEARING

IMPAIRED PERSON. THE DISCLOSURE RELATES SPECIFICALLY TO A

METHOD OF IMPROVING A USER'S PERCEPTION OF A SPEECH SOUND.

THE APPLICATION RELATES TO AN AUDIO PROCESSING DEVICE AND TO ITS USE LIKE ALL KINDS OF HEARING AIDS AND COCHLEAR IMPLANTS

THE APPLICATION FURTHER RELATES TO A DATA PROCESSING SYSTEM COMPRISING A PROCESSOR AND PROGRAM CODE MEANS FOR CAUSING THE PROCESSOR TO PERFORM AT LEAST SOME OF THE STEPS OF THE METHOD.

THE DISCLOSURE MAY E.G. BE USEFUL IN APPLICATIONS SUCH AS

COMMUNICATION DEVICES, E.G. TELEPHONES, OR LISTENING DEVICES, E.G. HEARING INSTRUMENTS, HEADSETS, HEAD PHONES, ACTIVE EAR PROTECTION DEVICES OR COMBINATIONS THEREOF.

BACKGROUND ART

THE FOLLOWING ACCOUNT OF THE PRIOR ART RELATES TO ONE OF THE AREAS OF APPLICATION OF THE PRESENT APPLICATION, HEARING AIDS.

THE FOLLOWING COMPENSATING WAYS FOR THE LOSS OF HEARING DESCRIBED IS TO TRANSFER THE FREQUENCY RANGES AFFECTED INTO OTHER FREQUENCY RANGES, WHICH CAN BE BETTER PERCEIVED.

FREQUENCY-LOWERING SCHEMES(SIMPSON A: FREQUENCY-LOWERING DEVICES FOR MANAGING HIGH-FREQUENCY HEARING LOSS: A REVIEW. TRENDS AMPLIF. 13(2): 87-106 (2009))

THIS SECTION AIMS TO DESCRIBE THE MORE COMMONLY USED METHODS OF IMPLEMENTING FREQUENCY LOWERING

1- CHANNEL VOCODERS

ENVELOPES OF SIGNALS IN HIGH-FREQUENCY BANDS ARE

ESTIMATED AND USED TO MODULATE THE AMPLITUDES OF AN EQUAL NUMBER OF SIGNAL GENERATORS, WHICH PRODUCE EITHER PURE TONES OR NARROW-BAND NOISES AT FREQUENCIES LOWER THAN THOSE OF THE CORRESPONDING FILTERS.

DISADVANTAGES/EARLY VOCODERS DIDN'T DISTINGUISH

BETWEEN VOICED AND VOICELESS SOUNDS, NON-SPEECH LIKE SOUND QUALITY.

2- SLOW PLAYBACK

A METHOD OF FREQUENCY LOWERING THAT RECORDS SEGMENTS OF THE SPEECH SIGNAL AND THEN PLAYS THESE SEGMENTS BACK AT A SLOWER SPEED THAN THAT USED IN THE ORIGINAL RECORDING, WITH THE RESULTING OUTPUT SIGNAL LENGTHENED IN TIME AND LOWERED IN FREQUENCY.

DISADVANTAGES: STRETCHING THE SIGNAL IN TIME. THIS CAN CAUSE THE INPUT AND OUTPUT SIGNALS TO BE DES YNCHRONI ZED IN TIME. SAMPLES OF THE SIGNAL HAVE TO BE DELETED TO REDUCE THIS SIDE EFFECT OF THE PROCESSING. BUT SEGMENT DELETION CAN CAUSE DISTORTION OR DISCARD USEFUL SPEECH INFORMATION. - TRANSPOSITION

SHIFTS HIGH-FREQUENCY SOUNDS TO LOWER FREQUENCIES AND ADD TRANSPOSED SIGNAL TO UNPROCESSED LOWER FREQUENCY SIGNAL.

DISADVANTAGES: THE OVERLAP OF HIGH- AND LOW-FREQUENCY INFORMATION CAN BE DETRIMENTAL AS THE ADDED HIGH- FREQUENCY INFORMATION CAN MASK USEFUL LOW-FREQUENCY INFORMATION AS WELL AS TRANSPOSING UNWANTED HIGH- FREQUENCY BACKGROUND NOISE. - NONLINEAR FREQUENCY COMPRESSION

LOWER FREQUENCIES UNPROCESSED, HIGHER FREQUENCIES COMPRESSED IN GREATER AMOUNTS.

DISADVANTAGES:DOES NOT PRESERVE HARMONIC RELATIONSHIP BETWEEN FREQUENCY COMPONENTS - LINEAR FREQUENCY COMPRESSION

LOWERS ALL FREQUENCY COMPONENTS DOWNWARD BY A CONSTANT FACTOR

DISADVANTAGES: LOWERS PITCH OF SPEAKER, UNNATURAL SOUND QUALITY DISCLOSURE OF INVENTION

IN AUDIOLOGY AND PSYCHOACOUSTICS THE TERM CRITICAL BAND, INTRODUCED BY (FLETCHER H: SPEECH AND HEARING IN

COMMUNICATION NEW YORK: VAN NOSTRAN (1953)) REFERS TO THE FREQUENCY BANDWIDTH OF THE "AUDITORY FILTER" CREATED BY THE COCHLEA, THE SENSE ORGAN OF HEARING WITHIN THE INNER EAR.

A PERCEPTION-BASED SCALE, SUCH AS THE BARK, ERB OR SPINC SCALE. REGARDING BARK(TABLE 1), REFERENCE IS MADE TO (ZWICKER E AND FASTL H: PSYCHO ACOUSTICS-FACTS AND MODELS (2ND EDITION, (1999)), REGARDING ERB, REFERENCE IS MADE TO (MOORE B AND

GLASBERG B: SUGGESTED FORMULAE FOR CALCULATING AUDITORY- FILTER BANDWIDTHS AND EXCITATION PA TTERNS. J. ACOUST. SOC. AM., VOL. 74, NO. 3, PP. 750-753, (1983)), AND REGARDING SPINC, REFERENCE IS MADE TO (TERHARD TE: THE SPINC FUNCTION FOR SCALING OF

FREQUENCY IN AUDITORY MODELS. ACUSTIKA, NO. 77, P.4042 (1992)).

IT MUST BE POINTED OUT THAT THE MEASUREMENTS TAKEN SO FAR INDICATE THAT THE CRITICAL BANDS HAVE A CERTAIN WIDTH, I.E. THE COCHLEA NEED THE COMPLEX SOUND FORMANTS TO BE AT SPECIFIC DISTANCE FROM EACH OTHER TO BE PERCEIVED SEPARATELY.

A FORMANT IS A CONCENTRATION OF ACOUSTIC ENERGY AROUND A PARTICULAR FREQUENCY IN THE SPEECH WAVE.

FORMANTS ARE DISTINCTIVE FREQUENCY COMPONENTS OF THE ACOUSTIC SIGNAL PRODUCED BY SPEECH. THE INFORMATION THAT HUMANS REQUIRE TO DISTINGUISH BETWEEN SPEECH SOUNDS CAN BE REPRESENTED PURELY QUANTITATIVELY BY SPECIFYING PEAKS IN THE AMPLITUDE/FREQUENCY SPECTRUM.

PHONEME IS THE SMALLEST UNIT OF SPEECH THAT CAN BE USED TO MAKE ONE WORD DIFFERENT FROM ANOTHER WORD. EACH SPECIFIC LANGUAGE (E.G. ENGLISH, FRENCH ETC.) HAS ITS OWN PHONEMES AND EACH OF THESE PHONEMES HAS ITS FREQUENCY OF OCCURRENCE IN CONVERSATION AND ITS IMPORTANCE IN THAT LANGUAGE SPEECH INTELLIGIBILITY.

EACH PHONEME IN EVERY LANGUAGE HAS FORMANTS THAT DIFFERFROM THE OTHER PHONEMES AND THESE FORMANTS FOR A SPECIFIC PHONEME ARE DIFFERENT ACCORDING THE TALKER FLTNDAMENTAL FREQUENCY AS IT DIFFER AMONG MALE, FEMALE AND CHILDREN.(TABLE2).

RANKING THE CRITICAL BANDS AS WE KNOW THERE IS A NUMBER OF CRITICAL FREQUENCY

BANDSWITHIN THE COCHLEA ACCORDING TO THE PERCEPTION SCALES THEORIES.

IN HEARING LOSS PERSON SOME OF THE CRITICAL BANDS WILL BE NON-FUNCTIONING SO SOME OF THE INFORMATION WITHIN THESE BANDS WILL BE LOST.

IF WE CONSIDER THE FORMANTS OF THE PHONEMES OF ALL WORLD WIDE LANGUAGES IN MALE, FEMALE AND CHILDREN; ALMOST ALL THE FREQUENCY CRITICAL BANDS WITHIN THE COCHLEA WILL BE IMPORTANT FOR SPEECH DISCRIMINATION.

> BUT IF WE CAN IDENTIFY THE FOLLOWING INFORMATION:-

1- THE LANGUAGE(E.G. ENGLISH, FRENCH ETC.) OF THE TALKER

(THROUGH THE HEARING AID WEARER SELECTION).

2- THE FLTNDAMENTAL FREQUENCY OF THE TALKER (THROUGH THE SOUND PROCESSOR REAL TIME ANALYSIS OF THE SPEECH SIGNAL). 3- THE IMPORTANCE OF EACH LANGUAGE PHONEME IN SPEECH

DISCRIMINATION.

4- THE FREQUENCY OF OCCURRENCE OF EACH LANGUAGE PHONEME IN CONVERSATION.

> THEN WE CAN RANK THE CRITICAL BANDS ACCORDING TO ITS

IMPORTANCE THROUGH FOLLOWING:- A- THE NUMBER OF PHONEMES FORMANTS IN EACH CRITICAL BAND FOR THE SPECIFIED TALKER LANGUAGE AND FUNDAMENTAL FREQUENCY.

B- IMPORTANCE OF EACH PHONEME IN SPEECH DISCRIMINATION C- THE FREQUENCY OF OCCURRENCE OF EACH LANGUAGE PHONEME

IN CONVERSATION.

❖ THE AIM OF THE TALKER FUNDAMENTAL FREQUENCY INCLUSION IS THAT A SPECIFIC FREQUENCY BAND COULD BE IMPORTANT FOR A SPECIFIC TALKER WITH A SPECIFIC FUNDAMENTAL FREQUENCY (E.G. MALE) AND NOT IMPORTANT FOR ANOTHER TALKER WITH ANOTHER

FUNDAMENTAL FREQUENCY (E.G. FEMALE) AND VISE VERA, SO WE RECOGNIZE THE LEAST IMPORTANT BANDS FOR EACH SPECIFIC TALKER THROUGH HIS FUNDAMENTAL FREQUENCY.

BAND SPECIFIC FREQUENCY LOWERING SCHEME MOST OF FREQUENCY LOWERING SCHEMES ACTS ON THE WHOLE

FREQUENCY RANGE E.G. LINEAR FREQUENCY COMPRESSION OR ON A PART OF FREQUENCY RANGE E.G. NON-LINEAR FREQUENCY

COMPRESSION BUT BOTH TYPES HAS ITS DISADVANTAGES THAT HINDER SPEECH RECOGNITION ESPECIALLY IN THE AREA OF THE PROCESSED SIGNAL.

THE BAND SPECIFIC FREQUENCY LOWERING SCHEME INCORPORATES MAKING THE FREQUENCY LOWERING SCHEMES ACT ON THE LEAST IMPORTANT CRITICAL BANDS AND KEEP THE MOST IMPORTANT FREQUENCY BANDS UNCHANGED AS MUCH AS POSSIBLE.

THIS TECHNIQUE WILL LIMIT THE DISADVANTAGES OF FREQUENCY

LOWERING TECHNIQUES TO THE LEAST IMPORTANT CRITICAL BANDS ACCORDING TO A SPECIFIC TALKER LANGUAGE(E.G. ENGLISH, FRENCH ETC.), FUNDAMENTAL FREQUENCY, PHONEMES IMPORTANCE IN SPEECH DISCRIMINATION AND FREQUENCY OF OCCURRENCE OF PHONEMES IN CONVERSATION.

SEE COMPARISON BETWEEN FREQUENCY AREAS AFFECTED BY THE FREQUENCY LOWERING SCHEMES.FIG (1). ACCORDING TO ALL PREVIOUS FACTS WE CAN INCREASE THE

PERCEPTION OF THE SPEECH SOUNDS BY FOLLOWING STEPS:

1- THE HEARING APPARATUS USED MUST HAVE BAND PASS FILTERS CREATING FREQUENCY BANDS THAT BAND WIDTH EQUAL TO A PERCEPTION-BASED SCALE, SUCH AS THE BARK, ERB OR SPE C SCALE AND POSSIBLY LOWER NUMBER OF BANDS IF WE CONSIDER SOME OF THE CRITICAL BANDS ARE NOT IMPORTANT FOR SPEECH PERCEPTION.

2- RANK THEFREQUENCY BANDS FROM THE LEAST TO THE MOST IMPORTANT FOR EACH TALKER FUNDAMENTAL FREQUENCY ACCORDING TO A SPECIFIC LANGUAGE PHONEMES FORMANTS NUMBER IN EACH BAND, EVERY PHONEME IMPORTANCE IN

SPEECH RECOGNITION AND EACH PHONEME FREQUENCY OF OCCURRENCE IN CONVERSATION.

3- DURING FITTING THE PROCESSOR OF HEARING APPARATUS

CALCULATE THE LOST CRITICAL BANDS FROM THE AUDIOGRAM, NOTE THAT THIS TECHNIQUE CAN BE USEWITH ANY HEARING LOSS CONFIGURATION (NOT ONLY THE HIGH FREQUENCY LOSS).

4- DURING FITTING OF THE HEARING APPARATUS, THE WEARER

MUST CHOOSE THE PREFERRED LANGUAGE OR LANGUAGESOF HIS EVERY DAY USAGE TO BE CHOSEN AS INDIVIDUAL PROGRAMS IN FITTING STEP.

5- AFTER FITTING THE HEARING AIDS MUST IDENTIFY THE

FUNDAMENTAL FREQUENCY OF THE TALKER THEN A FREQUENCY LOWERING SCHEME (E.G. COMPRESSION OR TRANSPOSITION) ACT MAINLY ON THE LEAST IMPORTANT CRITICAL BANDS IN A WAY THAT KEEP THE DIFFERENCES IN FORMANTS FREQUENCIES BETWEEN LANGUAGE PHONEMES FORMANTS UNTIL REDEEM ALL LOST BANDS. EXAMPLE

125 1- WE SUPPOSE THAT THE WEARER PREFERRED LANGUAGE IS

ENGLISH AND WE WILL CONSIDER THE CENTER FREQUENCIES OF THE LING SOUNDS AS LANGUAGE PHONEMES THEN WE WILL SET FORMANTS FOR ONE FUNDAMENTAL FREQUENCY (E.G. MALE)AND BARK SCALE AS EXAMPLE FOR A PERCEPTION SCALE. TABLE(3)

130 2- WE SUPPOSE THAT THE HEARING IMPAIRED HAD POOR

THRESHOLDS ABOVE 1.5 KHZ (LIKE HEARING LOSS MORE THAN 80 DB) AS THE IMPORTANT SPEECH FREQUENCY RANGE EXPAND ONLY TO ABOUT 6 KHZ THEN WE WILL CONSIDER THE NEEDED CRITICAL BANDS TO NO. 20 (CENTER FREQUENCY 5.8 KHZ) ONLY

135 AND EXCLUDE THE LAST FOUR BANDS, THEN ACCORDING TO

HEARING LOSS( ABOVE 1.5 KHZ) THE LOST BANDS FROM NO.(12) WITH CENTER FREQUENCY OF (1.6 KHZ) TO NO. 20 WITH CENTER FREQUENCY (5.8 KHZ) SO LOST BANDS IS 9, THEN WE WILL

SUPPOSE THAT ALL PHONEMES HADTHE SAME IMPORTANCE IN

140 SPEECH INTELLIGIBILITY AND SAME FREQUENCY OF OCCURRENCE

IN THE SPECIFIC LANGUAGE CONVERSATION.

3- WE PUT THE FORMANTS OF THE PHONEMES ON THE NORMAL

CRITICAL BANDS. TABLE (4). THEN FREQUENCY LOWERING

SCHEME (FREQUENCY COMPRESSION IN THIS EXAMPLE WILL BE

145 USED) FOR EACH FUNDAMENTAL FREQUENCY WILL COMPRESS

THE LEAST IMPORTANT FREQUENCY BANDS AND THEN SHIFT THE NEARBY BANDS IN DIRECTION OF BETTER HEARING. IN THIS EXAMPLE THE BANDS HAS THE LEAST NO. OF FORMANTS WITHIN IT AS WE SUPPOSED THAT ALL PHONEMES HAD THE SAME

150 IMPORTANCE IN SPEECH INTELLIGIBILITY AND SAME FREQUENCY

OF OCCURRENCE IN CONVERSATION, SO WE COMPRESS THE LEAST IMPORTANT FREQUENCY BANDS (4, 5, 6) BY A COMPRESSION FACTOR 3, COMPRESS FREQUENCY BANDS (9, 10, 1 1, 12) BY A COMPRESSION FACTOR 4, COMPRESS THE BANDS (14,15, 16) BY A 155 COMPRESSION FACTOR 3 AND FINALLY COMPRESS BANDS (17,18,

19) BY A COMPRESSION FACTOR 3. (TABLE 5).

4- AFTER FITTING THE PROCESSOR WILL RECOGNIZE THE

FUNDAMENTAL FREQUENCY OF THE TALKERTHEN USE THE ALREADY SET BANDS COMPRESSION PLAN FOR THAT SPECIFIC

160 FUNDAMENTAL FREQUENCY.

BRIEF DESCRIPTION OF THE TABLES

TABLE (1): CRITICAL BANDS WIDTHS ACCORDING TO BARKS SCALE.

TABLE (2): FORMANTS FREQUENCIES IN SOME ENGLISH PHONEMES IN MALE, FEMALE AND CHILDREN.

TABLE (3): LING SOUNDS FORMANTS (CENTER FREQUENCY).

TABLE (4):LING SOUNDS FORMANT DISTRIBUTION AMONG BARK SCALE BEFORE COMPRESSION, DC =DIRECTION OF COMPRESSION, C.F= BAND CUT-OFF FREQUENCY BEFORE COMPRESSION,

NO=NUMBER OF THE FREQUENCY BAND, CB= BANDS WILL BE COMPRESSED, F=FORMANT NUMBER IN EACH FREQUENCY BAND, CF=COMPRESSION FACTOR FOR EACH FREQUENCY BAND

TABLE (5):LING SOUNDS FORMANTS DISTRIBUTION AMONG BARK SCALE AFTER FREQUENCY BANDS COMPRESSION, C.F= BAND CUTOFF FREQUENCY BEFORE COMPRESSION, C.F.C-BAND CUT-OFF FREQUENCY AFTER COMPRESSION, NO=NUMBER OF THE

FREQUENCY BAND, CB =COMPRESSED FREQUENCY BANDS.

FIG (l):COMPARISON BETWEEN FREQUENCY AREAS AFFECTED BY THE FREQUENCY LOWERING SCHEMES, SHADED AREAS =

AFFECTED AREAS, 1= LOW FREQUENCY, 2= HIGH FREQUENCY, 3= LINEAR FREQUENCY COMPRESSION, 4= NON-LINEAR FREQUENCY COMPRESSION, 5= FREQUENCY TRANSPOSITION, 6= BAND SPECIFIC FREQUENCY LOWERING SCHEME

Claims

CLAIMS;-

1- A METHOD OF OPERATING AN AUDIO PROCESSING DEVICE TO IMPROVE A USER'S PERCEPTION OF AN INPUT SOUND, THE METHOD COMPRISING:CONVERTING BY THE AUDIO

PROCESSING DEVICE THE INPUT SOUND SIGNAL IN A NUMBER OF FREQUENCY BANDS CORRESPONDING TO A PERCEPTION SCALE , APPLYING "BAND SPECIFIC FREQUENCY LOWERING SCHEME" MAINLY ON THE LEAST IMPORTANT FREQUENCY BANDS ACCORDING TO THE TALKER LANGUAGE (E.G. ENGLISH, FRENCH ETC.) PHONEMES FORMANTS, FUNDAMENTAL

FREQUENCY, THE IMPORTANCE OF EACH OF THESE PHONEMES IN SPEECH RECOGNITION AND FREQUENCY OF OCCURRENCE OF EACH PHONEME IN CONVERSATION.

2- THE METHOD OF CLAIM 1, WHEREIN THE BAND PASS FILTERS OF THE HEARING APPARATUS ARE CORRESPONDING TO A PERCEPTION SCALE DEFINED BY ONE OF THE FOLLOWING FUNCTIONS: BARK FUNCTION; OR ERB FUNCTION; OR SPINC FUNCTION.

3- THE METHOD OF CLAIM 1, WHEREIN THE TYPE OF SPEECH

SIGNAL IS RECOGNIZED BY THE TALKER FUNDAMENTAL FREQUENCY AS IT DIFFERS AMONG MALE, FEMALE

ANDCHILDREN.

4- THE METHOD OF CLAIM 1, WHEREIN FREQUENCY LOWERING SCHEME APPLIED ON THE FREQUENCY AREAS THAT ARE DETERMINED ACCORDING TO THE LANGUAGE PHONEMES FORMANTS,FUNDAMENTAL FREQUENCY OF THE TALKER AS IT DIFFERS IN MALE, FEMALE, AND CHILDREN, IMPORTANCE OF PHONEMES IN SPEECH INTELLIGIBILITY AND FREQUENCY OF OCCLTRRENCE OF PHONEMES IN CONVERSATION OF A SPECIFIED LANGUAGE. 5- THE METHOD OF CLAIM 1, RANKING OR MODIFICATION OF THE FREQUENCY BANDS ACCORDING TO THE LANGUAGE PHONEMES FORMANTS , FUNDAMENTAL FREQUENCY OF THE TALKER AS IT DIFFERS IN MALE, FEMALE, AND CHILDREN, IMPORTANCE OF PHONEMES IN SPEECH INTELLIGIBILITY OF A SPECIFIED LANGUAGE AND FREQUENCY OF OCCURRENCE OF PHONEMES IN CONVERSATION OF A SPECIFIED LANGUAGE.

6- THE METHOD OF CLAIM 1, WHEREIN SELECTIVE BAND

FREQUENCYLOWERINGACT MAINLY ON THE LEAST IMPORTANT BANDS IN A WAY THAT KEEP THE DIFFERENCES IN FORMANTS FREQUENCIES IN THE SPECIFIED LANGUAGE.

7- A HEARING ASSISTANCE APPARATUS, COMPRISING, A

MICROPHONE CONFIGURED TO RECEIVE AN ACOUSTIC INPUT SIGNAL AND TO PRODUCE AN AUDIO SIGNAL;

FREQUENCYFILTERS CONFIGURED TO RECEIVE THE AUDIO SIGNAL AND GENERATE FILTEREDFREQUENCY BANDS CORRESPONDING TO APERCEPTION SCALEAPPLYING "BAND SPECIFIC FREQUENCY LOWERING SCHEME" MAINLY ON THE LEAST IMPORTANT FREQUENCY BANDS ACCORDING TO THE TALKER LANGUAGE(E.G. ENGLISH, FRENCH ETC.) PHONEMES FORMANTS, FUNDAMENTAL FREQUENCY, THE IMPORTANCE OF EACH OF THESE PHONEMES IN SPEECH RECOGNITION AND FREQUENCY OF OCCURRENCE OF EACH PHONEME IN CONVERSATION.

8- THE APPARATUS OF CLAIM 7, WHEREIN THE BAND PASS

FILTERS OF THE HEARING APPARATUS ARE CORRESPONDING TO A PERCEPTION SCALE OF HUMAN EAR DEFINED BY ONE OF THE FOLLOWING FUNCTIONS: BARK FUNCTION; OR ERB

FUNCTION; OR SPINC FUNCTION.

9- THE APPARATUS OF CLAIM 7, WHEREIN THE TYPE OF SPEECH SIGNAL IS RECOGNIZED BY THE TALKER FUNDAMENTAL FREQUENCY AS IT DIFFERS AMONG MALE, FEMALE AND

CHILDREN.

10- THE APPARATUS OF CLAIM 7, WHEREIN FREQUENCY LOWERING SCHEME APPLIED ON THE FREQUENCY AREAS THAT ARE DETERMINED ACCORDING TO THE LANGUAGE PHONEMES FORMANTS, FUNDAMENTAL FREQUENCY OF THE TALKER AS IT DIFFERS IN MALE, FEMALE, AND CHILDREN, IMPORTANCE OF PHONEMES IN SPEECH INTELLIGIBILITY AND FREQUENCY OF OCCURRENCE OF PHONEMES IN CONVERSATION OF A SPECIFIED LANGUAGE.

11- THE APPARATUS OF CLAIM 7, RANKING OR MODIFICATION OF THE FREQUENCY BANDS ACCORDING TO THE LANGUAGE PHONEMES FORMANTS .FUNDAMENTAL FREQUENCY OF THE TALKER AS IT DIFFERS IN MALE, FEMALE, AND CHILDREN, IMPORTANCE OF PHONEMES IN SPEECH INTELLIGIBILITY OF A SPECIFIED LANGUAGE AND FREQUENCY OF OCCURRENCE OF PHONEMES IN CONVERSATION OF A SPECIFIED LANGUAGE.

12- THE APPARATUS OF CLAIM 7, WHEREIN SELECTIVE BAND

FREQUENCY LOWERINGACT MAINLY ONTHE LEAST IMPORTANT BANDS IN A WAY THAT KEEP THE DIFFERENCES IN FORMANTS FREQUENCIES IN THE SPECIFIED LANGUAGE.