CN201845545U

CN201845545U - Voice activity detector

Info

Publication number: CN201845545U
Application number: CN2010206008413U
Authority: CN
Inventors: 付俊秀; 唐永伦; 王生平; 王明鹏; 奉鸣; 谢亮
Original assignee: Mianyang Netop Telecom Equipment Co Ltd
Current assignee: Mianyang Netop Telecom Equipment Co Ltd
Priority date: 2010-11-11
Filing date: 2010-11-11
Publication date: 2011-05-25
Anticipated expiration: 2020-11-11

Abstract

A voice activity detector is characterized by the inclusion of a four-wire interface PTT (Push-To-Talk) converter, an A/D converter, a digital signal processor (DSP), a D/A converter and a control circuit, wherein the A/D converter is connected with the four-wire interface PTT converter; the DSP is connected with the A/D converter; the D/A converter is connected with the DSP; and the four-wire interface PTT converter and the DSP are mutually connected through the control circuit arranged therebetween. When the voice activity detector accesses to a commanding and dispatching machine, by the aid of various communication network equipment accessing to the commanding and dispatching machine and the exchange functions, the voice activity detector can achieve remote bidirectional calling and communication with commanding and dispatching machine users, PSTN (Public Switched Telephone Network) users, private network telephones, GSM (Global System for Mobile Communications) mobile phones, CDMA (Code Division Multiple Access) mobile phones, satellite phones and the like, and make breakthrough on the traditional approach that a wireless station can only communicate with a common-frequency broadcasting stationgeneous network users with a limited distance, thereby providing convenient communication means for various hetero to upload information and give command.

Description

Effective speech pick-up unit

Technical field:

The utility model relates to people's air defence, public security, People's Armed Police, meteorological departments emergency command communication system applications field, particularly realizes effective speech pick-up unit of two-way automatic calling and control between wireless station and other communication facilities.

Background technology:

Clearly propose in " Emergent Public Events the emergency response system construction plan (framework) " that country works out, rely on emergency command platforms at different levels, focus the consruction on emergent on-the-spot integrated command system, realize information interaction, guarantee the consistance of emergency information, ageing and completeness.

In " Chinese emergency communication technology and the business innovation symposial " held in 2009, relevant departments have proposed the reply strategy and the thinking of development of China's emergency communication, point out: the organizing and commanding ability and the emergency disposal ability that must further improve solution of emergent event, guarantee that the emergency communication managing rapidly, efficiently, carry out in an orderly manner, satisfy communication support and communication recovery requirements of one's work under the emergency case, that guarantees to communicate by letter is safe and smooth.

Summary of the invention:

The purpose of this utility model is to adopt the voice signal of Digital Signal Processing identification phone and wireless station, the calling, switching, the radio station PTT (emission control) that are used to control between communicating terminals such as wireless station and phone, mobile phone switch and two-way communication, and then design a kind of effective speech pick-up unit.

For achieving the above object, the utility model is taked following technical scheme:

A kind of effective speech pick-up unit, the formation that it is characterized in that this device comprises: four-wire interface PTT converter, the A/D converter that is connected with four-wire interface PTT converter, the digital signal processor DSP that is connected with A/D converter, the D/A converter that is connected with digital signal processor DSP, and be connected in control circuit between four-wire interface PTT converter and the digital signal processor DSP.

Further scheme is: also be provided with status information and control signal imput output circuit in the control circuit.

In the utility model:

Four-wire interface PTT converter: introduce the voice and the PTT signal of wireless station's (PTT wireless devices such as all kinds of short-wave radio sets, ultrashort wave radio set, cluster Vehicle mounted station), and finish the switching of PTT.

A/D converter: the digital signal that analog signal conversion is become PCM (pulse code modulation (PCM)) coding.

Digital signal processor DSP: the signal to input carries out processing such as filtering, Echo Cancellation, speech detection, voice storage, provides and discern various types of signal sound in the calling-up process.

D/A converter: convert the pcm encoder digital signal to simulating signal.

Control circuit: comprise microprocessor, storer, reset circuit, functions such as the control information in demonstration, digital signal processing and the radio station of the control that realization is switched PTT, the mould/number conversion of signal, duty and data processing.

The utility model mainly provides a kind of general design idea of effective speech pick-up unit, and described four-wire interface PTT converter, A/D converter, digital signal processor DSP, D/A converter, control circuit etc. can adopt traditional circuit common device.

The utility model has the advantages that: in emergency communication system, be equipped with multiple communication facilitiess such as satellite earth station, portable microwave, mobile phone, wireless station, command scheduling machine, satisfy user independence or associating networking and multiple communication requirement under various environment.Detect (VAD) by effective speech and install the voice communication that can realize between wireless station and plurality of devices such as satellite earth station, mobile phone and command scheduling machine, remedy the limited deficiency in signal of radio set overlay area, expanded the communication range and the distance in radio station.

Description of drawings:

Fig. 1 is effective speech pick-up unit theory diagram.

Fig. 2 is effective speech pick-up unit Application of Interface theory diagram.

Fig. 3 is that effective speech pick-up unit typical case uses block diagram.

Embodiment:

Below in conjunction with accompanying drawing the utility model is done detailed description.

As Fig. 1, a kind of effective speech pick-up unit, the formation that it is characterized in that this device comprises: four-wire interface PTT converter, the A/D converter that is connected with four-wire interface PTT converter, the digital signal processor DSP that is connected with A/D converter, the D/A converter that is connected with digital signal processor DSP, and be connected in control circuit between four-wire interface PTT converter and the digital signal processor DSP.Also be provided with status information and control signal imput output circuit in the control circuit.

Wherein:

DSP part implementation method can be as follows:

● bi-directional speech detects

Networking working method in radio station adopts the single-simplex operation mode, during with the wire user intercommunication, must promptly control the sending and receiving state of simplex station by detection wire user speech " have, do not have " in the two/single worker's conversion that has line end to carry out.

Promptly be in accepting state after the start of radio station, wait speech from the far-end radio station.Judge by " have, do not have " of detecting the radio station speech whether the someone calls out wire user.

● Echo Cancellation and filtering

When radio signals linked to each other with telephone wire, because of the radio station voice are four line modes (sending and receiving separate, each a pair of line), the voice of phone were two-way (a pair of lines of transmit-receive sharing), have therefore adopted differential networks to do the conversion of two or four lines.The impedance at differential networks two ends does not match and will cause signal reflex, i.e. echo.For the speech of reliable detection remote subscriber, prevent mistake with echo as voiceband user, therefore echo must be suppressed.The adaptive algorithm that adopts DSP has designed sef-adapting filter and has offset echo under different circuit typess and the different transmission range situations.

● the speech storage

When the employing speech detects the transmitting-receiving conversion of controlling the radio station, because of speech detection, the switching in radio station, radio station all need time overhead from switching to the stages such as steady operation, bring speech to cut sound (prev word or a few word that wire user is spoken can't hear in the radio station) inevitably.DSP adopts and will delay time a break time (this time is greater than the steady operation time after switching from the speech detection to the radio station) from the voice signal storage of wired side, re-sends to four-wire interface, and this mode has been avoided cutting the sound phenomenon effectively, has guaranteed speech quality.Storage time is adjustable to adapt to all types of radio station.

● the detection threshold of floating

Signal level when wired speech arrives DSP because of factors such as line quality, distance, catv terminal signal power and undesired signal are different is also different.Therefore DSP carries out frequency domain conversion, Energy Estimation, Noise Estimation to received signal, the realization of estimated snr scheduling algorithm is automatic adjusts decision threshold and judges noise or voice, guarantees the reliable detection of speech.

● signal tone continues

DSP can produce and call identifying prompt tone (as the dialing tone of 450Hz, busy tone, ring-back tone etc.) and touch-tone signal.

In conjunction with shown in Figure 1, be with calling-up wire user flow process:

● the radio station is under the receiving mode, inserts four-wire interface from the voice in radio station and output to the A/D converting unit after protection, isolation and impedance matching;

● input that the PCM digital signal that the A/D converting unit converts 64Kb/s to gives that DSP partly carries out filtering, Echo Cancellation, speech detects and dual-tone multifrequency collects the digits;

● notify control circuit after DSP detects speech, control circuit receives and tells wired side apparatus when there is speech in the radio station that wire user judges whether receipt of call;

● after detecting dual-tone multifrequency, DSP notifies control circuit, control circuit is told wired side apparatus with the dual-tone multifrequency number of receiving, wired side apparatus collects the digits immediately, and judge whether that activation continues, judge it is to call out this machine user if collect the digits, then complete connection receives calling-up, sends ring-back tone to the radio station; Can realize radio station selective call wire user (this step is only applicable to send the radio station or the cluster mobile telephone of dual-tone multifrequency, otherwise skips over this step) by the DTMF pulsing mode;

● talk behind the wire user receipt of call, the PCM digital signal that the speech of wire user converts 64Kb/s to through the D/A converting unit gives that DSP partly stores, filtering, Echo Cancellation and speech detect;

● notify control circuit detect the voice of wire user as DSP after, control circuit notice PTT conversion portion output PTT signal (low), the control radio station switches to sending mode;

● DSP exports to the wire user speech of storage the A/D converting unit and converts simulating signal to, outputs to the radio station behind the PTT conversion portion, has realized that wire user says that the radio station is listened;

● when DSP partly detects wire user and does not speak, tell control circuit, control circuit notice PTT conversion portion output PTT signal (height), the control radio station switches to receiving mode, speech from the radio station is exported to wire user through A/D conversion, DSP, D/A conversion, and this moment, wire user can be listened to the radio station speech;

● behind the end of conversation, provide busy tone, when DSP detects busy-back signal, tell control circuit as wired side, control circuit notice PTT conversion portion output PTT signal (height), the control radio station switches to receiving mode.

In sum: DSP detects wireless side and has or not voice to judge whether wireless side makes a call; Detecting wired side has or not voice to realize wired side apparatus and PTT wave point dialog interaction control and treatment.

Among Fig. 2, the wireless side of this device can insert PTT wireless devices such as all kinds of short-wave radio sets, ultrashort wave radio set, cluster Vehicle mounted station; Wired side of device can insert that satellite ground station phone, GSM access terminal, CDMA accesses terminal, all kinds of programme-controlled exchange and IP switch etc.Can realize carrying out between PTT wireless station and line termination unit point-to-point communication by Fig. 2 use.

In the typical case of Fig. 3 uses, this device is inserted the command scheduling machine, by all kinds of communication network equipment and function of exchange that the command scheduling machine inserts, PTT wireless station can select to carry out remote bi-directional call, conversation with command scheduling machine user, PSTN (public telecommunication network) user, private network phone, GSM mobile handset, CDMA mobile phone, satellite phone etc.Broken through wireless station can only with the traditional approach of in limited distance, communicating by letter with radio station frequently, expanded the application of wireless station energetically, extended the communication distance of wireless station, for various heterogeneous network users upload information, assign order command means of communication easily is provided.

Claims

1. effective speech pick-up unit, the formation that it is characterized in that this device comprises: four-wire interface PTT converter, the A/D converter that is connected with four-wire interface PTT converter, the digital signal processor DSP that is connected with A/D converter, the D/A converter that is connected with digital signal processor DSP, and be connected in control circuit between four-wire interface PTT converter and the digital signal processor DSP.

2. effective speech pick-up unit according to claim 1 is characterized in that: also be provided with status information and control signal imput output circuit in the control circuit.