JPH0818517A - Voice codec - Google Patents
Voice codecInfo
- Publication number
- JPH0818517A JPH0818517A JP15192294A JP15192294A JPH0818517A JP H0818517 A JPH0818517 A JP H0818517A JP 15192294 A JP15192294 A JP 15192294A JP 15192294 A JP15192294 A JP 15192294A JP H0818517 A JPH0818517 A JP H0818517A
- Authority
- JP
- Japan
- Prior art keywords
- voice
- mobile communication
- communication terminal
- data
- digital
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Analogue/Digital Conversion (AREA)
- Transmission Systems Not Characterized By The Medium Used For Transmission (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、デジタル移動体通信端
末等の機器における音声コーデックに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice codec in equipment such as a digital mobile communication terminal.
【０００２】[0002]
【従来の技術】従来のデジタル移動体通信端末におけ
る、送信部（符号化部），受信部（復号化部）から構成
される音声コーデックに関し、符号化部は、音声信号を
アナログ−デジタル変換器（ＡＤＣ）でデジタル信号に
変換し、音声コーデック内においてデジタル圧縮処理を
行なう。復号化部は、圧縮処理されたデジタル信号を復
号化し、デジタル−アナログ変換器（ＤＡＣ）で音声信
号に変換し出力する。かかる、音声コーデックではデジ
タル音声圧縮処理に起因する雑音を発生し、聴感上の音
質の劣化が既に、避けられないものとなっている。2. Description of the Related Art In a conventional digital mobile communication terminal, a speech codec composed of a transmission section (encoding section) and a receiving section (decoding section), wherein the encoding section converts an audio signal into an analog-digital converter. (ADC) converts into a digital signal, and digital compression processing is performed in the audio codec. The decoding unit decodes the compressed digital signal, converts the digital signal into a voice signal by a digital-analog converter (DAC), and outputs the voice signal. In such an audio codec, noise resulting from the digital audio compression processing is generated, and the deterioration of the sound quality in hearing is already inevitable.
【０００３】[0003]
【発明が解決しようとする課題】本発明の第一の目的
は、音声コーデックにおいてデジタル音声圧縮処理に起
因する歪の発生を特殊な信号処理を必要なしにかつ、消
費電力，実装面積を増大させることなく音質の改善をは
かる音声コーデックを提供する。SUMMARY OF THE INVENTION A first object of the present invention is to increase the power consumption and the mounting area of a voice codec without the need for special signal processing for the occurrence of distortion due to digital voice compression processing. To provide a voice codec that improves the sound quality without the need.
【０００４】本発明の第二の目的は、移動体通信端末各
々の使用者が使用者自身に合わせて音質の改善度を選択
できる音声コーデックを提供する。A second object of the present invention is to provide a voice codec in which the user of each mobile communication terminal can select the degree of improvement in sound quality according to the user himself.
【０００５】[0005]
【課題を解決するための手段】上記第一の目的は、音声
コーデック内の復号化出力に音声信号通過帯域内に遮断
周波数を持つフィルターを挿入することにより、音質の
改善が可能となり達成できる。The first object can be achieved by inserting a filter having a cut-off frequency in the audio signal pass band into the decoded output in the audio codec so that the sound quality can be improved.
【０００６】上記第二の目的は、音声コーデック内の復
号化出力に音声通過帯域内に遮断周波数を持つフィルタ
を複数個挿入することにより、移動体通信端末使用者の
操作で切り換えることが可能となり達成できる。The second object is to insert a plurality of filters each having a cutoff frequency within the voice pass band in the decoded output of the voice codec so that the mobile communication terminal user can perform switching. Can be achieved.
【０００７】[0007]
【作用】デジタル移動体通信端末において音声コーデッ
クの復号化処理の出力に音声信号通過帯域内に遮断周波
数を持つフィルターを挿入することにより、デジタル音
声圧縮処理に起因する音質の劣化を聴感上低減，改善を
容易に実現され得る。By inserting a filter having a cutoff frequency within the audio signal pass band in the output of the audio codec decoding process in the digital mobile communication terminal, the deterioration of the sound quality due to the digital audio compression process is audibly reduced. Improvements can be easily realized.
【０００８】また、上記音声通過帯域内フィルタを複数
種類挿入し、移動体通信端末使用者が任意に切替ること
により、使用者自身に合わせて聴感上の音質の改善度を
切替ることが容易に実現され得る。Further, by inserting a plurality of types of the above-mentioned voice pass band filters and allowing the mobile communication terminal user to arbitrarily switch, it is easy to switch the degree of improvement in the sound quality in the sense of hearing according to the user himself / herself. Can be realized in.
【０００９】[0009]
【実施例】以下、本発明を図１〜図３を用いて説明す
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS.
【００１０】本発明に係る音声コーデックが適用される
移動体通信端末のハードウェア構成を図１を用いて説明
する。The hardware configuration of the mobile communication terminal to which the voice codec according to the present invention is applied will be described with reference to FIG.
【００１１】本発明に係る音声コーデックが適用される
移動体通信端末は、高周波信号の送信，受信を行う無線
高周波部１と、信号の変調，復調を行うモデム部２と、
移動体通信端末全体の制御を行う制御部３と、移動体通
信端末使用者が操作するキー操作部４と、音声信号のデ
ジタル−アナログ，アナログ−デジタル変換器５と、ス
ピーカー６およびマイク７から構成される。The mobile communication terminal to which the voice codec according to the present invention is applied has a radio high frequency section 1 for transmitting and receiving high frequency signals, a modem section 2 for modulating and demodulating signals.
From the control unit 3 for controlling the entire mobile communication terminal, the key operation unit 4 operated by the user of the mobile communication terminal, the digital-analog and analog-digital converter 5 of the audio signal, the speaker 6 and the microphone 7. Composed.
【００１２】受信動作を説明すると、無線高周波部１で
信号処理（周波数変換）した信号(ＩＦ信号）８をモデ
ム部２でデータ復調し、デジタル音声データー９を本発
明に係る音声コーデックに入力し、復号化部で音声圧縮
データの復号化を行い、音声データ１０をディジタル−
アナログ変換器５に出力し、アナログ音声信号１２をス
ピーカー７に出力する。The reception operation will be described. A signal (IF signal) 8 signal-processed (frequency-converted) by the radio frequency unit 1 is demodulated by the modem unit 2, and digital voice data 9 is input to the voice codec according to the present invention. , The decoding unit decodes the compressed audio data and digitally converts the audio data 10.
The analog audio signal 12 is output to the analog converter 5, and the analog audio signal 12 is output to the speaker 7.
【００１３】送信動作を説明すると、マイク７からアナ
ログ音声信号１２を入力し、アナログ−デジタル変換器
５から音声データ１０を音声コーデックに入力し、符号
化部で音声圧縮データの符号化を行い、デジタル音声デ
ータ９をモデム部２でデータ変調し、無線高周波部１で
高周波信号に変調し、送信を行う。To explain the transmission operation, the analog voice signal 12 is input from the microphone 7, the voice data 10 is input to the voice codec from the analog-digital converter 5, and the voice compression data is encoded by the encoding unit. The digital voice data 9 is data-modulated by the modem unit 2 and is modulated by the wireless high-frequency unit 1 into a high-frequency signal for transmission.
【００１４】今、本発明に係る音声コーデック内復号部
の構成を図２を用いて説明する。Now, the configuration of the decoding unit in the voice codec according to the present invention will be described with reference to FIG.
【００１５】デジタル音声データーを取り込み一時的に
保管をするデータバッファ２１，音声圧縮データの復号
をする復号化部２２及び、低域通過フィルタ（ＬＰＦ）
部２３から構成する。ＳＷ１〜ＳＷｎ２４は、移動体通
信端末使用者がスピーカー６から出力されるアナログ音
声信号を評価しながら図１のキー操作部４により選択す
る。A data buffer 21 for taking in digital audio data and temporarily storing it, a decoding unit 22 for decoding compressed audio data, and a low pass filter (LPF).
It comprises the unit 23. SW1 to SWn24 are selected by the user of the mobile communication terminal using the key operation unit 4 of FIG. 1 while evaluating the analog audio signal output from the speaker 6.
【００１６】ＬＰＦの作用について、図３を用いて説明
する。The action of the LPF will be described with reference to FIG.
【００１７】実線部３１は、ＬＰＦの特性曲線を表す。
１〜ｎは、ＬＰＦの遮断周波数の違いを表す。点線部示
す範囲ｆｗは、スピーカー６から出力されるアナログ音
声信号の周波数帯域を表し、矢印Ｎｉは、デジタル音声
圧縮処理により発生する雑音を表す。The solid line portion 31 represents the characteristic curve of the LPF.
1 to n represent differences in cutoff frequencies of LPFs. The range fw indicated by the dotted line represents the frequency band of the analog audio signal output from the speaker 6, and the arrow Ni represents the noise generated by the digital audio compression processing.
【００１８】つまり、デジタル音声圧縮処理により発生
する歪をＬＰＦ３１により遮断し、かつ遮断周波数の異
なるＬＰＦを任意の１〜ｎ種類設け、キー操作部を移動
体通信端末使用者が任意に操作することによりＬＰＦを
１〜ｎ任意に切換る。That is, the distortion generated by the digital audio compression process is blocked by the LPF 31, and any 1 to n kinds of LPFs having different cutoff frequencies are provided, and the mobile communication terminal user can arbitrarily operate the key operation unit. The LPF is arbitrarily switched by 1 to n.
【００１９】[0019]
【発明の効果】以上説明したように、音声コーデック内
の復号化部の出力に音声帯域内に遮断周波数を持つ低域
通過フィルターを設けることにより、デジタル音声圧縮
処理に起因する雑音の発生による音質の劣化を低減する
ことが容易にできる。As described above, by providing a low-pass filter having a cutoff frequency in the voice band at the output of the decoding unit in the voice codec, the sound quality due to the noise generated by the digital voice compression processing is provided. Can be easily reduced.
【００２０】ならびに、異なった遮断周波数を持つ任意
の複数種類の低域通過フィルターを音声コーデック内の
復号化部の出力に設け、移動体通信端末使用者のキー操
作部の操作により任意の遮断周波数の低域通過フィルタ
を選択することにより、音質の劣化の低減度合いを、移
動体通信端末使用者個々に選択することが容易にでき
る。Further, arbitrary plural kinds of low-pass filters having different cutoff frequencies are provided at the output of the decoding unit in the voice codec, and the cutoff frequencies can be set by operating the key operation unit of the user of the mobile communication terminal. By selecting the low-pass filter of, it is possible to easily select the degree of reduction in deterioration of sound quality for each user of the mobile communication terminal.
【図１】本発明の移動体通信端末のハードウェアの構成
図である。FIG. 1 is a hardware configuration diagram of a mobile communication terminal of the present invention.
【図２】本発明の音声コーデックの構成図である。FIG. 2 is a configuration diagram of a voice codec of the present invention.
【図３】本発明の音声コーデック内に設ける低域通過フ
ィルターの特性図である。FIG. 3 is a characteristic diagram of a low-pass filter provided in the audio codec of the present invention.
１…無線高周波部、２…モデム部、３…制御部、４…キ
ー操作部、５…デジタル−アナログ，アナログ−デジタ
ル変換器、６…スピーカー、７…マイク、８…ＩＦ信
号、９…デジタル音声データ、１０…音声データ、１１
…アナログ音声信号、２１…データバッファ、２２…復
号化部、２３…低域通過フィルター、２４…低域通過フ
ィルター切換用ＳＷ１〜ｎ、３１…低域通過フィルター
特性曲線、ｆｗ…アナログ音声帯域、Ｎｉ…雑音。DESCRIPTION OF SYMBOLS 1 ... Wireless high frequency part, 2 ... Modem part, 3 ... Control part, 4 ... Key operation part, 5 ... Digital-analog, analog-digital converter, 6 ... Speaker, 7 ... Microphone, 8 ... IF signal, 9 ... Digital Voice data, 10 ... Voice data, 11
... analog voice signal, 21 ... data buffer, 22 ... decoding unit, 23 ... low pass filter, 24 ... low pass filter switching SW1 to n, 31 ... low pass filter characteristic curve, fw ... analog voice band, Ni ... noise.
Claims (2)
なう音声符号，復号化処理部（音声コーデック）におい
て、復号化部出力に音声帯域のフィルターを挿入したこ
とを特徴とする音声コーデック。1. A voice codec in which a voice band filter is inserted at the output of the decoding unit in a voice code / decoding processing unit (voice codec) for performing voice compression in a digital mobile communication terminal.
末使用者の操作により、該フィルターの遮断周波数を選
択することを特徴とする音声コーデック。2. A voice codec according to claim 1, wherein a cutoff frequency of the filter is selected by a user operation of a mobile communication terminal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15192294A JPH0818517A (en) | 1994-07-04 | 1994-07-04 | Voice codec |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15192294A JPH0818517A (en) | 1994-07-04 | 1994-07-04 | Voice codec |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0818517A true JPH0818517A (en) | 1996-01-19 |
Family
ID=15529138
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15192294A Pending JPH0818517A (en) | 1994-07-04 | 1994-07-04 | Voice codec |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0818517A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6584308B2 (en) | 1997-11-18 | 2003-06-24 | Nec Corporation | Mobile telephone with voice data compression and recording features |
-
1994
- 1994-07-04 JP JP15192294A patent/JPH0818517A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6584308B2 (en) | 1997-11-18 | 2003-06-24 | Nec Corporation | Mobile telephone with voice data compression and recording features |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2730868B2 (en) | Audio system and method for increasing intelligibility | |
| US6714796B1 (en) | Mobile communication terminal device | |
| KR100541344B1 (en) | Wcdma mobile device of transmissible multi-channel sounds | |
| MXPA03010711A (en) | Apparatus and method for reducing power consumption in a mobile unit. | |
| JPH0818517A (en) | Voice codec | |
| KR20010091979A (en) | Device for shaping a signal, notably a speech signal | |
| JP2755056B2 (en) | Digital communication wireless telephone | |
| US7080017B2 (en) | Frequency compander for a telephone line | |
| JP2000286741A (en) | Digital wireless microphone system | |
| JP2007158614A (en) | Mobile phone and method for adjusting received sound | |
| JP4705556B2 (en) | Wireless microphone transmitter, receiver and system | |
| US8185042B2 (en) | Apparatus and method of improving sound quality of FM radio in portable terminal | |
| KR100479204B1 (en) | Apparatus for eliminating noise of audio signal and method thereof | |
| CN221710079U (en) | Multifunctional wireless tour guide audio equipment | |
| JP2001285409A (en) | Telephone set | |
| JP4222695B2 (en) | Digital wireless microphone system | |
| KR19990068334A (en) | handphone having a recording /playing function for music/voice | |
| JPH07254878A (en) | Digital mobile radio equipment | |
| JPH09148950A (en) | Digital broadcasting reception equipment | |
| JPH08340267A (en) | Transmitter-receiver with background noise reduction function | |
| JP3764339B2 (en) | Voice communication system | |
| JPH10150692A (en) | Digital wireless microphone device, transmitter and receiver | |
| KR100608769B1 (en) | Voice signal output circuit for mobile phone | |
| KR20040097639A (en) | Mobile Phone having Function of Playing Melody by Selective Filter and Method for Playing | |
| JPH1013243A (en) | Voice recording/reproducing method and digital portable telephone set |