CN1581717A - Apparatus for transmitting telephone signal in coaxial cable - Google Patents
Apparatus for transmitting telephone signal in coaxial cable Download PDFInfo
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- CN1581717A CN1581717A CN 03153403 CN03153403A CN1581717A CN 1581717 A CN1581717 A CN 1581717A CN 03153403 CN03153403 CN 03153403 CN 03153403 A CN03153403 A CN 03153403A CN 1581717 A CN1581717 A CN 1581717A
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- pass filter
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Abstract
The device includes low pass filter module, high-pass filter module and interface conversion module. The low pass filter module connected to output end of coaxial line through interface conversion module converts between telephone signal transferred on coaxial line and telephone signal transferred on twisted-pair. The said high-pass filter is connected to output end of coaxial line and input end of cable TV signal. The invention takes full advantage of bandwidth resources and cheap general telephone equipment to provide phone service. Thus, it is convenient for cable TV provider to provide telephone service as well as lowers cost for providing telephone service.
Description
Technical field
The present invention relates to the communications field, relate in particular to a kind of device in the transmission over coaxial cable telephone signal.
Technical background
At present a lot of families have all opened cable TV and phone, and what wherein cable TV adopted is the coaxial cable transmission, and phone adopts the twisted-pair feeder transmission.
Cable TV signal is by modulation system the analog or digital TV signal to be modulated in the frequency range of 46M--860M at present, and is sent in the user family by the cable TV radio frequency cable.The twisted-pair feeder telephone signal comprises dtmf signal, telephone speech signal, feed, bell signal etc.The frequency range of dtmf signal and call voice analog signal is 300hz--3400hz, and feed is a direct current signal, is sent by the phone local side apparatus, and common is-48V also can be other voltage range.Bell signal is the low frequency signal (can provide 25HZ as the CC08 switch, the bell signal of 75V) of＜100HZ.
The active user watches the cable TV of numeral or simulation by cable tv coax, and inserts phone by twisted pair telephone.General cable television operators have the cable tv coax resource, but do not have twisted-pair feeder.Therefore can't adopt traditional telephony to provide telephone service for the user.Can only use the CableModem technology to provide IP-based phone scheme as the user.And need provide Cable Modem equipment for user side based on the access technology of Cable Modem, multimedia terminal adapter (MTA) for local side provides CMTS equipment, requires cable of cable TV to carry out bidirectional rebuilding simultaneously, the user need buy relevant device, and investment and quantities are bigger.
Summary of the invention
Purpose of the present invention is exactly that a kind of device that utilizes coaxial cable to transmit telephone signal will be provided, thereby can be by this device, and utilizing at present, very cheap traditional telephony provides session services for the user.
For this reason, the present invention adopts following technical scheme:
A kind of device in the transmission over coaxial cable telephone signal is characterized in that comprising: low pass circuit module, high pass circuit module and interface conversion module;
Described low pass circuit module is connected in the coaxial cable output, by the interface conversion module twisted-pair feeder telephone signal that transmits on the single-ended telephone signal that transmits on the coaxial cable and the telephone terminal is changed;
Described high pass circuit module is connected in coaxial cable output and cable TV signal input.
Described low pass circuit module is a low pass filter.
The frequency passband scope of described low pass filter is smaller or equal to low-pass cut-off frequencies.
The low-pass cut-off frequencies of described low pass filter is greater than the used cut-off frequency of telephone signal.
The cut-off frequency of described low pass filter is less than the frequency range lower bound of cable TV signal.
Described high pass circuit module is a high pass filter.
The frequency passband scope of described high pass filter is more than or equal to high pass cut off frequency.
Described high pass filter can be passive high three-way filter or active high-pass filter.
Described interface conversion module has POTS interface and twisted-pair feeder interface, and described POTS interface connects the output of low pass circuit module, and described twisted-pair feeder interface connects telephone terminal or local side telephone terminal.
Described interface conversion module includes low-pass filter circuit and coupling circuit;
Described low-pass filter circuit carries out DC feedback signal and low-frequency dialling signal filtering and is sent to the POTS end;
Described coupling circuit is finished the coupling conversion of differential signal to single-ended signal.
Technical solution of the present invention is transmitted the technology of telephone signal simultaneously by adopting the coaxial cable transmission, the bandwidth resources and the present very cheap plain old telephone equipment that can make full use of coaxial cable provide telephone service, made things convenient for cable television operators that telephone service is provided, having reduced provides the telephone service cost.
Description of drawings
Fig. 1 is a coaxial cable transmission telephone signal technical scheme of the present invention;
Fig. 2 is a kind of realization circuit diagram of low pass filter among the present invention;
Fig. 3 is a kind of realization circuit diagram of high pass filter of the present invention;
Fig. 4 is that a kind of interface translation circuit of the present invention is realized circuit diagram;
Fig. 5 adopts phone application implementation schematic diagram of the present invention;
Fig. 6 is a signal schematic representation of the present invention.
Embodiment
Below in conjunction with Figure of description the specific embodiment of the present invention is described.
The invention provides a kind of device that utilizes coaxial cable to transmit telephone signal, very cheap traditional telephony provides phone for the user thereby can utilize at present, compares with the phone scheme based on Cable Modem, and cost is very low.
Technical scheme of the present invention is by a low pass circuit module and a high pass circuit module; the interface conversion module is formed; the function of this low pass circuit module and high pass circuit module is to realize the filtration of the signal of different frequency; the signal of control different frequency is walked different passages; at present; the device that can realize this filtering function is a lot; such as low pass filter and high pass filter commonly used; the present invention describes as example to use low pass filter and high pass filter; but its protection range is not limited thereto; can realize the low pass and the high pass circuit of correlation function,, all should drop within protection scope of the present invention according to the combination of mode of the present invention.
As shown in Figure 1, this low pass filter is connected in the coaxial cable of present transmission cable TV signal, and the output of filter is connected in telephone terminal by an interface conversion module, can be that telephone terminal also can be a local side apparatus here.
Low pass filter is common circuit element, and is very little for the low frequency signals decay that is lower than its cut-off frequency, and very big for the high-frequency signal decay that is higher than its cut-off frequency, thereby stoped passing through of the signal that is higher than cut-off frequency.
High pass filter of the present invention is connected in coaxial cable and cable TV input, is used for the signal that transmits on the coaxial cable is filtered.High pass filter is also to be common circuit function, and is very little for the signal impedance that is higher than its cut-off frequency, and very big for the signal attenuation that is lower than its cut-off frequency, thereby stoped passing through of the signal that is lower than cut-off frequency.
The cut-off frequency of the low-pass filtering of using among the present invention program requires greater than the used cut-off frequency of telephone signal, and promptly more than the 3400hz, cut-off frequency is less than the frequency range lower bound of cable TV signal simultaneously, promptly below the 46Mhz.
The low pass filter that uses among the present invention program can allow direct current signal to pass through, so that transmit feed and bell signal in the telephone signal.
The frequency passband scope of the low pass filter that the present invention program uses is DC (0 hertz)--f1 (low-pass cut-off frequencies), 3400hz＜f1＜46Mhz, its implementation can be passive low ventilating filter or active low-pass filter, a kind of realization circuit of low pass filter of the present invention as shown in Figure 2:
As can be seen from Fig. 2, it is connected to form by several inductance L 21--L27 and capacitor C 21--C29.
The frequency passband scope of employed high pass filter is f2 (high pass cut off frequency)～infinity among the present invention program.Its implementation can be passive high three-way filter or active high-pass filter, high pass filter a kind of realization circuit as shown in Figure 3.As can be seen from Fig. 3, high pass filter of the present invention is connected to form by several inductance L 31--L34 and capacitor C 31--C36.
Interface translation circuit of the present invention is used to realize the bi-directional conversion differential twisted pair signal and single-ended signal.Its function is being that single-ended signal is sent to low pass filter from the difference phone signal transition on the twisted-pair feeder of telephone terminal or phone local side apparatus, simultaneously the telephone bill end signal from low pass filter is become differential signal and is sent to telephone terminal or local side telephone plant.
The interface translation circuit realizes that circuit has a variety of.A kind of realization circuit that the present invention uses is as shown in Figure 4: as seen from the figure, DC feedback signal and low-frequency dialling signal be by L1--L3 and C1, and (low-pass cut-off frequencies＜300HZ) is sent to the POTS end to the low-pass filter circuit that C2 forms.And voice signal and dtmf signal be by C3--C12, and L4--L7, T1 signal finish differential signal (ring is tip) to the coupling conversion of single-ended signal pots.
The operation principle that the present invention is based on above technical scheme is as follows:
The transmission principle of two-way telephone signal: the telephone signal from telephone terminal or local side is difference low frequency signal (RING, TIP), be sent to interface die change piece by twisted-pair feeder, become single-ended signal POTS by the interface conversion, owing to be low frequency signal and direct current signal, can deliver on the heart yearn of cable tv coax by low pass filter, same is low frequency signal and direct current signal from the single-ended telephone signal on the cable tv coax heart yearn, can be sent to the interface conversion module by low pass filter, be sent to telephone terminal or local side apparatus through transferring the both-end differential signal to behind the interface conversion module.Low frequency signal can't arrive cable TV by high pass filter and receive and sending ending equipment.
For ease of understanding, below provide the signals transmission of telephone signal in a call, as shown in Figure 5, the local side switch provides the DC feedback signal, be sent to this equipment by ring1 and tip1 holding wire, this device translates is to be sent to the heart yearn of coaxial cable behind the single-ended signal, this equipment at user side is sent to phone with electric feed signal by ring2 and tip2 holding wire, realize the power supply of telephone set internal circuit, the user begins the dial telephone set dial-up circuit and produces into the dtmf signal, pass out to this equipment by ring2 and tip2 difference, this device translates is single-ended signal is sent to local side by coaxial cable core wire this equipment, being sent to telephone exchange after being converted to differential signal. it is called according to dial-up that telephone exchange is handled the back, set up path after the called connection, called voice signal is sent through this device translates to the coaxial cable single-ended signal is sent to this equipment of calling party by twisted-pair feeder from switch again, is converted to differential signal again and gives phone.In like manner the voice signal of caller phone is sent to the local side switch by this equipment of user side and this equipment of local side too.Thereby realize providing the function of phone by coaxial cable.
When the user is called out, local side can be sent bell signal passes out to local side by ring1 and tip1 this equipment, finish the transmission of signal on coaxial cable by this equipment of local side and this equipment of user side, be sent to subsets, the subscriber phone power ringing, the user picks up the telephone, and realizes that afterwards both sides converse.
The transmission of cable TV signal: the cable TV signal on the cable tv coax can not be delivered to telephone terminal or phone local side apparatus by low pass filter as high-frequency signal, but can be sent to the cable TV receiving terminal by high pass filter.
Telephone signal and the TV signal signal flow in this equipment is to as shown in Figure 6.As seen from the figure, cable TV signal and telephone signal can be carried on the coaxial cable simultaneously, like this, and for the user has brought very big convenience and economic interests.
Claims (10)
1, a kind of device in the transmission over coaxial cable telephone signal is characterized in that comprising: low pass circuit module, high pass circuit module and interface conversion module;
Described low pass circuit module is connected in the coaxial cable output, by the interface conversion module twisted-pair feeder telephone signal that transmits on the single-ended telephone signal that transmits on the coaxial cable and the telephone terminal is changed;
Described high pass circuit module is connected in coaxial cable output and cable TV signal input.
2, device as claimed in claim 1 is characterized in that described low pass circuit module is a low pass filter.
3, device as claimed in claim 2, the frequency passband scope that it is characterized in that described low pass filter is smaller or equal to low-pass cut-off frequencies.
4, device as claimed in claim 2, the low-pass cut-off frequencies that it is characterized in that described low pass filter is greater than the used cut-off frequency of telephone signal.
5, device as claimed in claim 2 is characterized in that the frequency range lower bound of the cut-off frequency of described low pass filter less than cable TV signal.
6, device as claimed in claim 1 is characterized in that described high pass circuit module is a high pass filter.
7, device as claimed in claim 6, the frequency passband scope that it is characterized in that described high pass filter is more than or equal to high pass cut off frequency.
8, device as claimed in claim 6 is characterized in that described high pass filter can be passive high three-way filter or active high-pass filter.
9, device as claimed in claim 1, it is characterized in that described interface conversion module, have POTS interface and twisted-pair feeder interface, described POTS interface connects the output of low pass circuit module, and described twisted-pair feeder interface connects telephone terminal or local side telephone terminal.
10, device as claimed in claim 9 is characterized in that described interface conversion module, includes low-pass filter circuit and coupling circuit;
Described low-pass filter circuit carries out DC feedback signal and low-frequency dialling signal filtering and is sent to the POTS end;
Described coupling circuit is finished the coupling conversion of differential signal to single-ended signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03153403 CN1581717A (en) | 2003-08-12 | 2003-08-12 | Apparatus for transmitting telephone signal in coaxial cable |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03153403 CN1581717A (en) | 2003-08-12 | 2003-08-12 | Apparatus for transmitting telephone signal in coaxial cable |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1581717A true CN1581717A (en) | 2005-02-16 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 03153403 Pending CN1581717A (en) | 2003-08-12 | 2003-08-12 | Apparatus for transmitting telephone signal in coaxial cable |
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| Country | Link |
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| CN (1) | CN1581717A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101150303B (en) * | 2006-09-22 | 2010-04-21 | 阿尔卡特朗讯公司 | Multiple order low pass filter for an xDSL splitter in a telecommunication system |
| CN102117998A (en) * | 2011-03-09 | 2011-07-06 | 安徽电信器材贸易工业有限责任公司 | Adaptor type IPTV (internet protocol television) user connecting line |
| CN102163782A (en) * | 2011-03-09 | 2011-08-24 | 安徽电信器材贸易工业有限责任公司 | Directly-connected internet protocol television (IPTV) user link |
| US8159927B2 (en) | 2007-02-16 | 2012-04-17 | Gennum Corporation | Transmit, receive, and cross-talk cancellation filters for back channelling |
| US8462759B2 (en) | 2007-02-16 | 2013-06-11 | Semtech Canada Corporation | Multi-media digital interface systems and methods |
-
2003
- 2003-08-12 CN CN 03153403 patent/CN1581717A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101150303B (en) * | 2006-09-22 | 2010-04-21 | 阿尔卡特朗讯公司 | Multiple order low pass filter for an xDSL splitter in a telecommunication system |
| US8159927B2 (en) | 2007-02-16 | 2012-04-17 | Gennum Corporation | Transmit, receive, and cross-talk cancellation filters for back channelling |
| US8462759B2 (en) | 2007-02-16 | 2013-06-11 | Semtech Canada Corporation | Multi-media digital interface systems and methods |
| CN101304393B (en) * | 2007-02-16 | 2013-07-17 | 西姆特科加拿大有限公司 | Multi-media digital interface systems and methods |
| CN102117998A (en) * | 2011-03-09 | 2011-07-06 | 安徽电信器材贸易工业有限责任公司 | Adaptor type IPTV (internet protocol television) user connecting line |
| CN102163782A (en) * | 2011-03-09 | 2011-08-24 | 安徽电信器材贸易工业有限责任公司 | Directly-connected internet protocol television (IPTV) user link |
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Open date: 20050216 |