CN1085457C - Improved audio alarm signal detection method and device for front-end user equipment - Google Patents

Improved audio alarm signal detection method and device for front-end user equipment Download PDF

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Publication number
CN1085457C
CN1085457C CN98116116A CN98116116A CN1085457C CN 1085457 C CN1085457 C CN 1085457C CN 98116116 A CN98116116 A CN 98116116A CN 98116116 A CN98116116 A CN 98116116A CN 1085457 C CN1085457 C CN 1085457C
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cas
signal
audio signal
telephone
audio
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Expired - Fee Related
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CN98116116A
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CN1208173A (en
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赖振兴
茆帮华
韩加国
高建中
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Inventec Corp
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Inventec Corp
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Abstract

The present invention relates to a method and a device for improving CAS audio error detection. A low-cost special wafer arranged in a telephone is used; when a small section of CAS audio signal is detected, a central processing unit is triggered to generate an interrupt signal, a speech signal of a near end user is shielded by a shielding circuit of the telephone, the time sequence of the rest CAS audio signals is detected and judged, and meanwhile, a speech signal of a far end user is monitored by using a speech detection circuit. Thus, the length of the CAS audio signal can be accurately measured by the telephone under the condition of no interference of the speech signals of the near end user and the far end user, and the truth or the falseness of the CAS audio signal is judged according to the defined length of a specification.

Description

A kind of method and device that improves the survey of customer headend equipment warning signal audio alarm
The present invention relates to method and device that a kind of CAS of improvement audio alarm is surveyed, mainly be to detect a bit of CAS (CPE Alert Signal (CPE warning signal) at telephone set, hereinafter to be referred as CAS, wherein CPE is the abbreviation of Customer Premises Equipment (customer headend equipment)) behind audio frequency (Tone) signal, can cover (Mute) to near-end (Near End) user's voice signal earlier, sequential to remaining CAS audio signal detects judgement again, and far-end (Far End) user's voice signal monitored, to determine under the situation of the voice signal interference that does not have near-end and remote subscriber, accurately measure the length of this CAS audio signal, and, judge the true and false of this CAS audio signal according to the defined length of specification.
Press, in the employed now various telephone set, except possessing traditional speech communication function, some more newly-designed telephone set still has the ability of data communication, that comparison is typical and commonly used in this data communication facility is calling party identity/calling wait (Caller ID Call Waiting, abbreviation CIDCW) recognition function, this function mainly is that exchange line by telecommunications company is with the telephone number of calling party, information such as name and other information, be sent on called party's the telephone set, and show by the display on called party's telephone set (as: LCDs), make the called party when receiving calls, can learn the identity of calling party by the display on called party's telephone set.
Technical, one possesses the telephone set of CIDCW recognition function, before receiving the CIDCW data that exchange line transmitted of telecommunications company, receive a CAS audio signal earlier, this signal is mainly in order to notify called party's telephone set, immediately following CIDCW data will be arranged behind this signal, therefore, how when telephone set detects the CAS audio signal, can avoid the voice signal interference of near-end and remote subscriber, receive the CAS audio signal like clockwork with the phone function that makes the called party, promptly become and whether can finish the prerequisite that receives these CIDCW data smoothly.After all, can receive the CAS audio signal like clockwork, the beginning can guarantee that data are thereafter received reliably, and this is the difficulty place that the regular phone machine can't effectively overcome technically.
According to the regulation of Britain about numbering SIN242 and SIN227 in the CIDCW specification, the CAS audio signal has the parameter characteristic shown in the subordinate list among Fig. 1.By this subordinate list as can be known, the frequency of CAS audio signal drops within the audiorange, therefore the voice signal of the near-end of telephone set and remote subscriber and extraneous various noises thereof all are detected as the CAS audio signal most probably by mistake, causing real CAS audio signal may be because of user's voice signal and extraneous various interference of noise, and can't be detected exactly, for example: as if interference because of voice signal and outside noise, cause the CAS audio signal discontinuous, send a telegraph phone and judge that this audio signal is not an effective CAS audio signal, and the CIDCW data that transmit of receipt of call side not, this is so-called allergy (Talk-down) performance during the CAS audio signal detects; Again,, desire interference, send a telegraph the phone erroneous judgement and receive a CAS audio signal, cause the malfunction of telephone set because of voice signal and outside noise if the telephone set of calling party does not transmit a CAS audio signal; This is so-called blunt excessively (Talk-off) performance during the CAS audio signal detects.
Press, the telephone set that generally possesses the CIDCW recognition function, consult shown in Figure 2, mainly comprise the custom wafer 11 (can be the custom wafer of a numbering Mitel 8843) that detects the CAS audio signal, speaking circuit 12, CPU 13, microphone 14, receiver 15, bridgt circuit (Bridge) 16, elements such as choosing discharge road 17 and LCDs 18, wherein A is passed through on choosing discharge road 17, the B signal end receives the data-signal that exchange line transmits, and be sent to custom wafer 11, detect whether receive a CAS audio signal by custom wafer 11, if, then triggering this CPU 13 receives immediately following CIDCW data behind this signal, and the calling party telephone number that these CIDCW data are comprised, name and other information etc., be sent on the LCDs 18, calling party and called party's voice signal is then by bridgt circuit 16, speaking circuit 12 and microphone 14 or receiver 15 are finished the work of linking up each other.
The method that this kind utilizes custom wafer 11 to detect, its advantage is a low price, implements simple.But because these custom wafer itself all do not possess anti-voice interference capability, so the factor that extraneous voice disturb still exists, causing the allergy that the CAS audio signal is detected and cross passivity can be very poor, can not reach the specification requirement of SR-TSV-002476 and the Britain BT of U.S. Bellcore.Review, the method that another kind utilizes digital signal processor (Digital Signal Process is called for short DSP) to detect though can obtain comparatively ideal allergy and cross the passivity energy, realizes that the difficulty of this method is very big, and becomes also high relatively.
The present invention is for effectively improving the disappearance of aforementioned conventional CAS audio-frequency detection, mainly be when telephone set detects the CAS audio signal, utilize cheap custom wafer, after detecting a bit of CAS audio signal, utilize the circuit that covers of regular phone machine immediately, voice signal to this near-end user covers, make this custom wafer detect judgement at the sequential of remaining CAS audio signal again, utilize the speech detection circuit that the voice signal of remote subscriber is monitored simultaneously, so, telephone set can be under the situation of the voice signal interference of determining no near-end and remote subscriber, measure the length of this CAS audio signal exactly, and according to the defined length of specification, judge the true and false of this CAS audio signal, make telephone set detecting the irritated of CAS audio signal and crossing on the passivity energy, all can reach the specification requirement of Bellcore and BT.
Fig. 1 is according to the regulation of Britain about numbering SIN 242 and SIN 227 in the CIDCW specification, the parameter characteristic that the CAS audio signal has;
Fig. 2 is a kind of hardware configuration schematic diagram of commonly using the telephone set that can detect the CAS audio signal;
Fig. 3 is the hardware configuration schematic diagram of telephone set of the detection CAS audio signal of this embodiment of the present invention;
Fig. 4 is the hardware configuration schematic diagram of testing circuit of the present invention;
Fig. 5 is a system flow schematic diagram of the present invention;
Fig. 6 is the waveform schematic diagram of the CAS audio signal at A point place among the present invention embodiment shown in Figure 1.
The present invention is directed to generally in order to detect the custom wafer of CAS audio signal, in measurement CAS audio signal The time, by capturing useful signal to confirming as the CAS audio signal, all need a period of time, in during this period of time, The interference of extraneous voice signal exists always, so if can confirm in this custom wafer the period of CAS audio signal In, the interference of near-end voice signals is covered earlier, simultaneously the voice signal of remote subscriber is monitored, With in the situation of the voice signal interference of guaranteeing not have near-end and remote subscriber, measure exactly this CAS audio frequency The length of signal, and carry out the true and false judgement of CAS audio signal, detect the CAS audio signal with Effective Raise Accuracy.
For more clearly expressing design concept of the present invention and technical characterictic, the spy enumerates a preferred embodiment, and conjunction with figs., is described in detail as follows:
In telephone set of the present invention, be that custom wafer 21 (can be the custom wafer of a numbering Mitel 8843) detects the CAS audio signal, its block hardware diagram as shown in Figure 3, mainly comprise the elements such as custom wafer 21, speaking circuit 22, CPU 23, microphone 24, receiver 25, bridgt circuit 26, choosing discharge road 27 and LCDs 28 that detect the CAS audio signal, these elements there is no different with the aforementioned element of commonly using the telephone set that can detect the CAS audio signal basically.But, the invention reside in choosing discharge road 27 and 21 of custom wafer and add switched circuit 31 (Switch), with switch data signal and voice signal, when making telephone set be in on-hook (On Hook) state, this CPU 23 can make the contact 311 and 312 on the switched circuit 31 connect, form a data channel, make this custom wafer 21 can pass through choosing discharge road 27, reception is by A, the data-signal that the B signal end transmits, when telephone set is in off-hook (Off Hook) state, 23 of this CPU make the contact 311 and 313 on the switched circuit 31 connect, form a voice channel, make custom wafer 21 can pass through high pass filter 33, reception is by speaking circuit 22 and 25 voice signals that transmit of receiver, high pass filter 33 is mainly in order to the following voice signal of a certain frequency of filtering (as: 2000Hz), to improve the signal to noise ratio of CAS audio signal.
Among the present invention, also be provided with a testing circuit 32, this testing circuit 32 is in order to the signal of 22 of bridge detection circuit 26 and speaking circuits, to have judged whether that voice signal exists, if have, then testing circuit 32 will be exported a high level signal to CPU 23, make this CPU 23 learn that voice signal exists.In an embodiment of the present invention, this testing circuit 32 can be made up of institutes such as bandwidth-limited circuit 321, rectification circuit 322 and level comparison circuit 323.Consult shown in Figure 4, wherein this bandwidth-limited circuit 321 is in order to take out a certain frequency range (as: 300~3400Hz) audio signal from bridgt circuit 26 and 22 of speaking circuits, rectification circuit 322 is in order to give rectification with this audio signal, to export a direct current level, 323 reference level comparisons in order to this DC level and is preset of level comparison circuit have voice signal if this DC level greater than this reference level, is promptly judged, otherwise, then do not exist.
Telephone set of the present invention is when reality is used, consult shown in Figure 5, Fig. 5 is a system flow schematic diagram of the present invention, when telephone set is in hook state, CPU 23 will be connected switched circuit 31 upper contacts 311 and 312, make custom wafer 21 by this choosing discharge road 27, reception is by A, the data-signal that the B signal end transmits, when telephone set is in off hook state, 23 of this CPU make the contact 311 and 313 on the switched circuit 31 connect, with the opening voice passage, make custom wafer 21 by high pass filter 33, receive by speaking circuit 22 and 25 voice signals that transmit of receiver, and the following voice signal of a certain frequencies of mat high pass filter 33 filterings (as: 2000Hz), whether transmit the CAS audio signal with detection, and whether this audio signal is effective.
When this custom wafer 21 detects the CAS audio signal, promptly trigger one and interrupt signal, make CPU 23 produce a shielded signal, speaking circuit 22 is carried out voice shielding action, with the near-end voice signals that screening of calls side is imported into via microphone 24, get rid of the interference of near-end speech.Then, CPU 23 is judged the sequential of removing the effective CAS audio signal after disturbing again, if the CAS audio signal remains valid, this testing circuit 32 promptly detects the signal of 22 of bridgt circuit 26 and telephone circuits, with monitoring and judge whether far-end has voice signal.
If testing circuit 32 detects the mistake tone signal of far-end, judge that then the CAS audio signal that is received is false CAS audio signal, at this moment, testing circuit 32 will be exported a high level signal to this CPU 23, make CPU 23 learn that voice signal exists, and send signal to this speaking circuit 22, to open microphone 24.
Otherwise if testing circuit 32 does not detect the voice signal of far-end, CPU 23 is promptly to being judged by the sequential of custom wafer 21 detected effective CAS audio signals, and calculates the time T m of CAS audio signal.
Consult shown in Figure 6, Fig. 6 is the detected CAS audio signal of a present embodiment sequential schematic diagram, wherein importing custom wafer 21 preceding CAS audio signal sequential length overalls is T4, specification definition according to aforementioned Bellcore, the T4 value is in 75ms arrives the scope of 85ms, and in the CAS audio signal sequential of custom wafer 21 outputs, T1 is the front end acknowledging time of custom wafer 21, promptly confirm the time that the CAS audio signal begins, this time is determined by hardware circuit, is assumed to be 10ms in the present embodiment, and T3 is the rear end acknowledging time of this custom wafer 21, promptly confirm the time that the CAS audio signal finishes, this time also by the hardware circuit decision, is assumed to be 5ms in the present embodiment, T2 is the software certification time, by learning T2=T4-T1 among the figure, should be 76ms in the scope of 75ms.
In the present invention, this CPU 23 is calculated custom wafer 21 detected CAS audio signal length and in fact be should be Tm=T2+T3, because of this CPU 23 is sayed, in this T3 time range, the CAS audio signal still is effectively output, and therefore, this CAS audio signal length should be at 70ms in the time range of 80ms, that is in this time range measured CAS simple signal, all can be considered to real CAS audio signal.
Therefore, when calculating Tm values greater than 80ms as if this CPU 23, judge that the CAS audio signal is false, at this moment, CPU 23 is sent signal to this speaking circuit 22, to open microphone 24.
Otherwise, when calculating the Tm values less than 80ms, will continue to calculate custom wafer 21 detected CAS audio signals as if CPU 23, when detected CAS signal is invalid, whether calculate the Tm value again greater than 70ms,, judge that the CAS audio signal is false if less than 70ms; If greater than 70ms, judge that then the CAS audio signal is for genuine, at this moment, CPU 23 will be connected the contact 311 and 312 on this switched circuit 31, to close voice channel, receive immediately following a CIDCW data-signal behind the CAS signal by CPU 23, and with calling party telephone number, name and other information etc. that this CIDCW data-signal comprised, be sent on the LCDs 28, and behind the data message of finishing receipt of call side, connect the contact 311 and 312 on the switched circuit 31 again, with opening voice passage and microphone 24.
Hence one can see that, in an embodiment of the present invention, custom wafer 21 is when detecting the CAS audio signal, only detect CAS audio signal and voice signal in the time simultaneously at T1 (10ms), and in follow-up detection time, then do not have the interference of near-end and far-end speech signal fully, therefore, should obtain splendid irritated and cross the passivity energy for the detection of CAS audio signal.
The above is preferred embodiment of the present invention.But the scope that the present invention advocated is not limited thereto.In every case be familiar with this skill personage, according to the disclosed technology contents of the present invention, can think easily and equivalence change, as: cooperate method of the present invention, adopt the method for other custom wafer or employing DSP, all should belong to and not break away from protection category of the present invention.

Claims (7)

1. one kind is improved the method that the CAS audio alarm is surveyed, set custom wafer is when detecting a bit of CAS audio signal on this method mat telephone set, microphone to this telephone set covers, to cover the voice signal of near-end user, and then the sequential of remaining CAS audio signal detected judgement, it is characterized in that, also simultaneously the voice signal of remote subscriber is detected, with monitoring and judge whether far-end has voice signal; When detecting the voice signal of far-end, this telephone set judges that the CAS audio signal that is received is false, and opens microphone; When not detecting the voice signal of far-end, this telephone set is promptly judged the sequential of the detected effective CAS audio signal of this custom wafer, and is calculated the duration T m of CAS audio signal.
2. the method for improving the CAS audio detection as claimed in claim 1, it is characterized in that, importing the preceding CAS audio signal sequential length overall of this custom wafer is T4, in the CAS audio signal sequential of this custom wafer output, confirm that the time that the CAS audio signal begins is T1, this time is determined by hardware circuit, confirm that the time that the CAS audio signal finishes is T3, this time is also determined by hardware circuit, its software certification time then is T2, T2=T4-T1 wherein, this telephone set calculate the duration T m of CAS audio signal in the time range of T2+T3, all can be considered to real CAS audio signal.
3. the method for improving the survey of CAS audio alarm as claimed in claim 1 or 2, it is characterized in that, if Tm is in the scope of T2+T3, then this telephone set judges that measured CAS audio signal is genuine, at this moment, close voice channel, receiving, and, shown calling telephone number, name and other information etc. that this data-signal comprised immediately following the stroke count number of it is believed that behind this CAS signal, and in finish receive this data-signal after, opening voice passage and microphone again.
4. the method for improving the survey of CAS audio alarm as claimed in claim 1 or 2 is characterized in that, outside the scope of T2+T3, this telephone set judges that promptly measured CAS audio signal is false, and opens microphone as if Tm.
5. one kind is improved the device that the CAS audio alarm is surveyed, and this device comprises:
CPU is in order to the running of each element in the control telephone set;
Custom wafer is in order to detect the CAS audio signal that is sent to this telephone set by exchange line; This custom wafer is when detecting a bit of CAS audio signal, can make this CPU that the microphone of this telephone set is covered, to cover the voice signal of near-end user, this custom wafer detects judgement to the sequential of remaining CAS audio signal more then;
It is characterized in that described device also comprises:
Testing circuit is in order to detect the voice signal that is sent to this telephone set by exchange line;
Described testing circuit comprises:
Bandwidth-limited circuit is in order to take out the audio signal of a certain frequency range in the voice signal of remote subscriber;
Rectification circuit is in order to this simple signal is given rectification, flat with output DC;
Level comparison circuit in order to this DC level and a reference level of presetting are compared, has voice signal if this DC level greater than this reference level, is promptly judged, otherwise, then do not exist;
Described testing circuit detects the voice signal of remote subscriber, to monitor and to judge whether far-end has voice signal, when detecting the voice signal of far-end, opens microphone by central processing unit controls; When not detecting the voice signal of far-end, described central processing unit is to being judged by the sequential of the detected effective CAS audio signal of described custom wafer, and calculates the duration T m of CAS audio signal.
6. the device that improves the survey of CAS audio alarm as claimed in claim 5, it is characterized in that, also comprise switched circuit, this switched circuit imports the data-signal or the voice signal of this custom wafer in order to switching, when making telephone set be in hook state, this CPU can make this switched circuit form a data channel, make this custom wafer can receive the data-signal that transmits by exchange line, when telephone set is in off hook state, this CPU can make this switched circuit form a voice channel, the mistake tone signal that this custom wafer can be received transmitted by exchange line.
7. the device that improves the survey of CAS audio alarm as claimed in claim 6 is characterized in that, also comprises high pass filter, and this high pass filter is in order to receive the voice signal that is sent to this custom wafer by exchange line, with the voice signal below a certain frequency of filtering.
CN98116116A 1998-07-16 1998-07-16 Improved audio alarm signal detection method and device for front-end user equipment Expired - Fee Related CN1085457C (en)

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CN98116116A CN1085457C (en) 1998-07-16 1998-07-16 Improved audio alarm signal detection method and device for front-end user equipment

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Application Number Priority Date Filing Date Title
CN98116116A CN1085457C (en) 1998-07-16 1998-07-16 Improved audio alarm signal detection method and device for front-end user equipment

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CN102651740A (en) * 2011-02-28 2012-08-29 阿尔卡特朗讯 Method and device for processing voice information

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5007076A (en) * 1988-08-08 1991-04-09 At&T Bell Laboratories Call announcement arrangement
US5263084A (en) * 1991-07-22 1993-11-16 Northern Telecom Limited Spontaneous caller identification with call-waiting
WO1996025825A1 (en) * 1995-02-13 1996-08-22 Cidco, Incorporated Method and structure for detecting a customer premises equipment alerting signal
US5649002A (en) * 1994-12-13 1997-07-15 Colonial Data Technologies Corp. Method and apparatus for detecting a telephone CPE alerting signal

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5007076A (en) * 1988-08-08 1991-04-09 At&T Bell Laboratories Call announcement arrangement
US5263084A (en) * 1991-07-22 1993-11-16 Northern Telecom Limited Spontaneous caller identification with call-waiting
US5649002A (en) * 1994-12-13 1997-07-15 Colonial Data Technologies Corp. Method and apparatus for detecting a telephone CPE alerting signal
WO1996025825A1 (en) * 1995-02-13 1996-08-22 Cidco, Incorporated Method and structure for detecting a customer premises equipment alerting signal

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