Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M9/00—Arrangements for interconnection not involving centralised switching
  • H04M9/08—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
  • H04M9/082—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic using echo cancellers
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
  • G06F3/16—Sound input; Sound output
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
  • G10L21/00—Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
  • G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
  • G10L21/0208—Noise filtering
  • G10L2021/02082—Noise filtering the noise being echo, reverberation of the speech
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
  • G10L21/00—Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility
  • G10L21/02—Speech enhancement, e.g. noise reduction or echo cancellation
  • G10L21/0208—Noise filtering
  • G10L21/0216—Noise filtering characterised by the method used for estimating noise
  • G10L2021/02161—Number of inputs available containing the signal or the noise to be suppressed
  • G10L2021/02165—Two microphones, one receiving mainly the noise signal and the other one mainly the speech signal
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M1/00—Substation equipment, e.g. for use by subscribers
  • H04M1/58—Anti-side-tone circuits

Definitions

• the invention relates to a Rechnergerat with multidirectional acoustic ⁇ off and -eingabesystem according to the preamble of claim 1.
• Telephone devices for example, have means for eliminating acoustic echo signals, so-called acoustic echo elimination circuits, also known as acoustic echo cancellers (AEC), which are coupled in by the handset of the telephone device through the room and the speech cup.
• AEC acoustic echo cancellers
• the Acoustic Echo Canceller is particularly important when speaking freely, i.e. without an acoustic signal device being held on the ear and mouth.
• An essential part of the Acoustic Echo Canceller is an adaptive filter.
• the task of the adaptive filter is to simulate the transfer function of the room.
• the Acoustic Echo Canceller receives the output signal, which is sent to the loudspeaker, on the one hand as a reference signal and, on the other hand, receives the input signal, which is introduced by the microphone into the system.
• the output signal follows two separate paths. Once it is applied directly and once it is led through the room through the loudspeaker and the microphone. If the filter is well adapted, the two ways are equivalent.
• the two paths are equivalent because, with a good adaptation, the adaptive filter exactly replicates the path of the output signal via the loudspeaker, the room and the microphone. The difference between the two signals is therefore at least almost zero. In this way the suppression of the echo is achieved.
• the echo can only be suppressed if the signal that reaches the loudspeaker and the signal that is picked up by the microphone correlate in time.
• a temporal correlation means that only one cons ⁇ aunt delay is present between the two mentioned signals.
• the signals arriving at the Acoustic Echo Canceller ie the signal that is output via the loudspeaker and the signal that is picked up by the microphone, do not correlate with one another in time. Once the adaptive acoustic echo canceller has been adjusted, it is therefore not sufficient to always suppress the echo.
• the acoustic signals applied to the adaptive filter of the acoustic echo canceller are namely the f o r the handset or speaker Rechnergerats be ⁇ agreed acoustic signal picked up by the microphone acoustic signal and independent of occurring variations in time delays of the components of the acoustic signals always correlated with each other in time.
• FIG. 1 shows a basic connection circuit of a filter of an acoustic echo canceller in a telephone arrangement according to the prior art
• FIG. 2 shows a basic functional circuit diagram of the output and input of acoustic signals in a computer device according to the prior art
• FIG. 3 shows a functional circuit diagram according to FIG. 3 with delay elements added in a basic manner
• FIG. 4 shows a functional circuit diagram according to FIG. 4 with an acoustic echo canceller shown in detail according to FIG. 1, and
• FIG. 5 shows a basic functional circuit diagram for the output and input of acoustic signals in a computer device according to the invention.
• FIG. 1 schematically shows an acoustic echo canceller, the core of which is an adaptive filter F.
• an acoustic signal to be output is conducted as an analog electrical signal via a line a to an input of the filter F and to a loudspeaker L.
• the loudspeaker L converts the analog electrical signal into an acoustic signal and radiates it into a room R.
• a Microphone M is received, the acoustic signal and a m e reshaped l ektwitzs analog signal.
• the analog signal is ü b via a line to a positive input of a circuit sums ⁇ S guided.
• An output signal of the filter F is fed to a negative input of the summation circuit S.
• a result signal of the summing circuit S is input to an averaging jerk Kopp ⁇ of the filter F led to Nachregel connectoren.
• the filter F is set in such a way that it compensates the delay circuit for a signal that travels the way from line a via loudspeaker L, room R, microphone M and line b, to the extent that the Input of the filter F applied signal arrives at the summation circuit S at the same time as the signal carried over the said route. In this way, an echo can be suppressed.
• the system shown in FIG. 1 has only a constant delay, so that the signals on lines a and b are temporally correlated.
• FIG. 2 shows the part of a personal computer that is relevant for outputting audio signals.
• This part comprises first means Ml for digitally processing or processing acoustic data to be output or received.
• This part also has second means M2 for processing for forwarding the acoustic data provided by the first means M1 for output or for processing for forwarding to the first means M1 of the acoustic data received.
• this part has third means M3, which are used to convert the acoustic data processed by the second means M2 for transmission into analog acoustic signals and to acoustically output the converted analog acoustic signals via lines a and the loudspeaker L via this case.
• the third means M3 also serve to convert the second means M2 m d igital acoustic data from constricting the microphone M and vorlie ⁇ case above about lines b recorded analog acoustic signals ⁇ .
• the first means Ml is at least in Tei of the figure l 2 formed round to G lying Rechnergerats by program control elements.
• the second means are formed by so-called drivers that are notwen ⁇ dig, to drive loading to specific parts of a random Rechnergerats.
• the third means M3 emulate a so-called sound card. The sound card converts m one direction digital signals into analog signals and m the other direction analog signals into digital signals.
• the loudspeaker L and the microphone are each acoustic converters.
• the loudspeaker L for example, represents a first and the microphone M a second acoustic transducer.
• the arrangement according to FIG. 2 has several paths to the loudspeaker or several paths from the microphone indicates that audio signals or acoustic signals can be output or recorded separately from one another on several channels, as is the case, for example, with stereo transmissions the case is.
• at least one further loudspeaker L or at least one further microphone M is then provided.
• an acoustic echo canceller can be used successfully in the personal computer despite the fact that multiple channels are used for the audio outputs or inputs in a personal computer.

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• Engineering & Computer Science (AREA)
• Theoretical Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• General Health & Medical Sciences (AREA)
• Human Computer Interaction (AREA)
• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Audiology, Speech & Language Pathology (AREA)
• Signal Processing (AREA)
• Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
• Circuit For Audible Band Transducer (AREA)
• Telephone Function (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 2000
  • 2000-03-16 DE DE10012868A patent/DE10012868C1/de not_active Expired - Fee Related
• 2001
  • 2001-03-16 CN CN01806624.0A patent/CN1201226C/zh not_active Expired - Fee Related
  • 2001-03-16 JP JP2001568182A patent/JP2003527806A/ja not_active Withdrawn
  • 2001-03-16 WO PCT/DE2001/001006 patent/WO2001069371A2/de not_active Application Discontinuation
  • 2001-03-16 US US10/221,898 patent/US7120246B2/en not_active Expired - Fee Related
  • 2001-03-16 EP EP01931367A patent/EP1264233A2/de not_active Withdrawn

Non-Patent Citations (1)

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