KR20110014387A - Mobile tv input filter circuit - Google Patents

Abstract

PURPOSE: A mobile TV input filter circuit is provided to continuously receive a digital TV broadcasting when a communication network is changed by converting a filtering pass. CONSTITUTION: A first telephone signal removing unit(100) eliminates a first telephone transmitting signal. The first switch(200) interlinks the output terminal of the first telephone signal delete to one of a first pass stage of a removing terminal. A second telephone signal delete(300) eliminates the second transmitting a call signal through the first elimination stage. A through pass(400) transfers the signal through the first pass stage. The second switch(500) interlinks one of the second elimination stage or the second pass stage to the output terminal.

Description

Mobile TV input filter circuit {MOBILE TV INPUT FILTER CIRCUIT}

The present invention relates to a mobile TV input filter circuit that can be applied to a mobile TV receiver. Particularly, when a mobile TV is received, the mobile TV input filter can be used even when the telephone network is changed by allowing the filtering path to be switched according to the telephone network. It is about a circuit.

In general, a mobile TV standard for receiving TV broadcasts between mobiles is undergoing commercial service through test broadcasts in each country and each market, and Korea is serving satellite-digital multimedia broadcasting (S-DMB). And Terrestrial-Digital Multimedia Broadcasting (T-DMB), Japan is the Integrated Service Digital Broadcasting-Terrestrial (ISDB-T), and Digital Audio Broadcasting (DVB-H) and Digital Audio Broadcasting (DVB-T), which are being promoted by Nokia in Europe. Terrestrial, China, China Multimedia Mobile Broadcasting (CMMB), USA, MediaFLO, and ATSC-M / H (Advanced Television Standards Committee-Mobile / Handheld) are promoting commercialization.

A set application that can adopt all of these different types of mobile TV standards is a mobile phone, a portable multimedia player (PMP), navigation, an MP3 (MPEG Audio Layer-3), a handheld game machine. Applications are in progress in various fields such as digital cameras and notebook PCs. Among the most popular products are mobile phones, which are being launched on the market with mobile TV receivers for each region.

In this case, while the mobile TV reception environment exists under a cellular transmission / reception system environment, in order to receive a broadcast signal smoothly, an exclusion circuit for cellular Tx in the phone must be installed inside the mobile TV receiver. Because different circuits need to be configured for different sales regions, the receiver must be implemented separately for each cellular system.

Referring to the conventional mobile TV receiver, when the mobile TV receiver is mounted on the telephone, a high power cellular transmission signal operates as a jammer of the mobile TV receiver. In this case, the mobile TV receiver includes a cellular transmission rejection filter (Tx rejection filter) at the input terminal.

As such, the standards most affected by cellular transmission signals are DVB-H, DVB-H, ISDB-T, CMMB, MediaFLO, ATSC-M / H, etc. This is because the band is adjacent to the 820-920 MHz band used for System for Mobile Communication transmission.

That is, the band pass filter (BPF) of the RF input terminal of the mobile TV receiver mounted on the mobile phone is a GSM communication cancellation filter. For example, when the GSM transmission signal is GSM 850, it is 824-849 MHz, and GSM 900 is In the case of 880 ~ 915MHz.

Accordingly, the bandpass filter includes a GSM900 cancellation filter, a GSM 850 & GSM900 removal filter, the GSM900 removal filter can remove a 880 to 915 MHz band, and the GSM850 & GSM900 removal filter is a 824 to 849 MHz and 880 to 915 MHz. All bands can be removed.

However, current mobile TV receivers have separate products with different filters depending on the cellular specification of the installed phone and the region where they are sold. Each receiver has a different filter and its associated peripheral circuits to match RF characteristics. There is a problem that it is different.

That is, the pass band of the filter is also different according to the rejection frequency. For example, in the case of the GSM900 elimination filter, the pass band is 470 to 800 MHz or 470 to 860 MHz, and then the GSM850 & GSM900 elimination filter. In this case, there is a problem that the passband is different from each other to 470 to 750 MHz or 470 to 770 MHz.

For this reason, the receiver manufacturer has to produce separate products separately, and the set maker has to make a distinctive receiver for each phone situation according to each phone situation, and when the phone is moved to another area ( Global Roaming Situation) If the cellular environment is different, there is a problem with mobile TV support.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above problems of the prior art, and its object is to allow mobile TV reception to be switched even when the telephone network is changed by switching the filtering path according to the telephone network. An input filter circuit is provided.

One technical aspect of the present invention for achieving the above object of the present invention, the first telephone signal removing unit for removing the first telephone transmission signal; A first switch connecting an output terminal of the first telephone signal removing unit to one of a first pass terminal and a first removing terminal; A second telephone signal removing unit connected to a first removing end of the first switch and removing a second telephone transmission signal from a signal through the first removing end; A through pass connected to a first pass end of the first switch and transmitting a signal through the first pass end; And a second switch for connecting one of a second elimination stage connected to the second telephone signal eliminator and a second pass stage connected to the through pass to an output stage.

In one technical aspect of the present invention, each of the first switch and the second switch is characterized in that for selecting one signal path of the second telephone signal removing unit and the through path according to the switching control signal.

The mobile TV input filter circuit of the present invention comprises: a telephone network search unit for searching a telephone network in service based on a telephone reception signal; And a switching controller for supplying the switching control signal according to a search result of the telephone network search unit to the first and second switches.

In addition, another technical aspect of the present invention, the first telephone signal removal unit for removing the GSM 900MHz telephone transmission signal; A first switch connecting an output terminal of the first telephone signal removing unit to one of a first pass terminal and a first removing terminal; A second telephone signal removing unit connected to a first removing end of the first switch and removing a GSM 850 MHz telephone transmission signal from a signal through the first removing end; A through pass connected to a first pass end of the first switch and transmitting a signal through the first pass end; And a second switch for connecting one of a second elimination stage connected to the second telephone signal eliminator and a second pass stage connected to the through pass to an output stage.

In another technical aspect of the present invention, each of the first switch and the second switch is characterized in that it selects one signal path of the second telephone signal remover and the through path according to a switching control signal.

The mobile TV input filter circuit of the present invention includes a telephone network search unit for searching whether a service network is GSM 900 or GSM850 based on a telephone reception signal; And a switching control signal for controlling the selection of the through pass in the case of the GSM 900 telephone network and controlling the selection of the second telephone signal removing unit in the case of the GSM 850 telephone network according to the search result of the telephone network searching unit. It further comprises a switching control unit for supplying to.

According to the present invention as described above, when the mobile TV is received, the filtering path can be switched according to the telephone network, so that it can be used even when the telephone network is changed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is not limited to the embodiments described, and the embodiments of the present invention are used to assist in understanding the technical spirit of the present invention. In the drawings referred to in the present invention, components having substantially the same configuration and function will use the same reference numerals.

1 is a block diagram of a mobile TV input filter circuit according to the present invention.

Referring to FIG. 1, a mobile TV input filter circuit according to the present invention includes a first telephone signal removing unit 100 for removing a first telephone transmission signal, and an output terminal C1 of the first telephone signal removing unit 100. ) Is connected to the first switch 200 connecting one of the first pass end PT1 and the first removal end RT1, and the first removal end RT1 of the first switch 200. A second telephone signal removing unit 300 which removes a second telephone transmission signal among signals through the first removing terminal RT1, and a first path terminal PT1 of the first switch 200, Through pass 400 for transmitting a signal through one pass stage PT1, a second pass stage RT2 connected to the second telephone signal remover 300, and a second pass coupled to the through pass 400. And a second switch 500 that connects one of the stages PT2 to the output stage C2.

Each of the first switch 200 and the second switch 500 has a structure for selecting one signal path of the second telephone signal remover 300 and the through path 400 according to a switching control signal.

In addition, the mobile TV input filter circuit according to the present invention, the telephone network search unit 600 for searching the telephone network in service based on the telephone reception signal and the switching control signal according to the search results of the telephone network search unit 600 It may include a switching control unit 700 for supplying the first and second switches (200, 500).

In one embodiment, the mobile TV input filter circuit according to the present invention, the first telephone signal removing unit 100 for removing the GSM 900MHz telephone transmission signal, and the output terminal (C1) of the first telephone signal removing unit 100 ) Is connected to the first switch 200 connecting one of the first pass end PT1 and the first removal end RT1, and the first removal end RT1 of the first switch 200. It is connected to the second telephone signal removing unit 300 for removing the GSM 850MHz telephone transmission signal of the signal through the first removing terminal (RT1), and the first pass terminal (PT1) of the first switch 200, Through pass 400 for transmitting a signal through a first pass end PT1, a second removal end RT2 connected to the second telephone signal remover 300, and a second pass connected to the through pass 400. And a second switch 500 that connects one of the pass stages PT2 to the output stage C2.

Each of the first switch 200 and the second switch 500 has a structure for selecting one signal path of the second telephone signal remover 300 and the through path 400 according to a switching control signal.

In addition, in one embodiment, the mobile TV input filter circuit according to the present invention includes a telephone network search unit 600 for searching whether a service network is GSM 900 or GSM850 based on a telephone reception signal, and the telephone network search unit 600. According to a search result of the GSM 900 telephone network to control the selection of the through pass 400, and if the GSM 850 telephone network switching control signal for controlling the selection of the second telephone signal removing unit 300 to the first and the second; It may include a switching control unit 700 for supplying the two switches (200, 500).

2 is an operational flowchart of a mobile TV input filter circuit according to the present invention. In FIG. 2, S100 is an operation process of searching for the telephone network currently being serviced by the telephone network searching unit 600. S200 is an operation process for determining whether the currently serving telephone network is a GSM 900 telephone network. S300 is an operation process of selecting a through pass as a signal path when the currently serving telephone network is a GSM 900 telephone network. S400 is an operation process of selecting a GSM 850 removal unit as a signal transmission path when the currently serving telephone network is not a GSM 900 telephone network.

3 is a pass frequency characteristic diagram at the time of selecting a through pass of the present invention. Referring to the graph shown in FIG. 3, when the through pass of the present invention is selected, it is understood that only the 900 MHz telephone transmission signal (880-915 MHz) of the received signal is removed by the first telephone signal removing unit 100 of the present invention. Can be.

4 is a pass frequency characteristic diagram at the time of selecting the second telephone signal removing unit of the present invention. Referring to the graph shown in FIG. 4, when the second telephone signal removing unit of the present invention is selected, the first telephone signal removing unit 100 and the second telephone signal removing unit 300 of the present invention transmit the 900 MHz signal. It can be seen that the telephone transmission signal (824-849 MHz) of 850 MHz is also removed along with the telephone transmission signal (880-915 MHz).

Hereinafter, the operation and effects of the present invention will be described in detail with reference to the accompanying drawings.

1 to 4, the mobile TV input filter circuit according to the present invention will be described. In FIG. 1, the mobile TV input filter circuit according to the present invention includes a first telephone signal removing unit 100 and a first switch. And a second phone signal remover 300, a through pass 400, and a second switch 500.

In this case, first, the first telephone signal removing unit 100 removes the first telephone transmission signal from the RF signal received through the first antenna ANT1. For example, when the first telephone transmission signal is a GSM 900 MHz telephone transmission signal, the first telephone signal removal unit 100 removes a frequency band of 880-915 MHz corresponding to the GSM 900 MHz telephone transmission signal.

Next, the first switch 200 and the second switch 500 operate in conjunction with each other to select the second telephone signal remover 300 or the through pass 400. Here, the operation of the first switch 200 and the second switch 500 may be made by a user's selection, or may be made by a switching control signal.

For example, the mobile TV input filter of the present invention is applied to a mobile device in which a GSM 900 MHz telephone network and a GSM 850 MHz telephone network are adjacent to each other, and move from the GSM 900 MHz telephone network to a GSM 850 MHz telephone network or from the GSM 850 MHz telephone network to a GSM 900 MHz telephone network. If a circuit is employed, for example, in a GSM 900 MHz telephone network, the through pass 400 is selected by the first switch 200 and the second switch 500. When the mobile device is moved from the GSM 900 MHz telephone network to the GSM 850 MHz telephone network, the second telephone signal removing unit 300 is selected by the first switch 200 and the second switch 500.

As another example, in the GSM 850MHz telephone network, the second telephone signal removing unit 300 is selected by the first switch 200 and the second switch 500. When the mobile device is moved from the GSM 850 MHz telephone network to the GSM 900 MHz telephone network, the through pass 400 is selected by the first switch 200 and the second switch 500.

That is, when the second telephone signal removing unit 300 is selected, the second telephone signal removing unit 300 corresponds to a telephone transmission signal of GSM 850 MHz among the signals from the first telephone signal removing unit 100. Remove the band 824MHz-849MHz.

In contrast, when the through pass 400 is selected, the through pass 400 transmits the signal from the first telephone signal remover 100 as it is.

Meanwhile, each of the first switch 200 and the second switch 500 selects one signal path of the second telephone signal remover 300 and the through path 400 according to a switching control signal. Explain.

The mobile TV input filter circuit according to the present invention may further include a telephone network search unit 600 and a switching controller 700. In this case, the telephone network search unit 600 searches for the telephone network in service based on the telephone reception signal. The switching controller 700 supplies the switching control signal according to the search result of the telephone network search unit 600 to the first and second switches 200 and 500.

Specifically, referring to FIGS. 1 and 2, the telephone network search unit 600 searches whether the telephone network in service is GSM 900 or GSM850 based on the telephone reception signal (S100 of FIG. 2). The switching control unit 700 determines whether the telephone network currently being serviced is the GSM 900 telephone network (S200).

The switching control unit 700 controls the selection of the through pass 400 in the case of the GSM 900 telephone network according to the search result of the telephone network search unit 600 (S300), and in the case of the GSM 850 telephone network, the second telephone signal system. The selection of the rejection 300 is controlled (S400).

3 and 4, the pass frequency characteristics of the case where the through pass 400 of the present invention is selected and the case where the second telephone signal canceller is selected will be described.

Referring to the graph shown in FIG. 3, when the through pass 400 of the present invention is selected, only the 900 MHz telephone transmission signal (880 MHz to 915 MHz) of the received signal is removed by the first telephone signal removing unit 100 of the present invention. Then, it can be seen that the transfer through the pass (400).

Referring to the graph shown in FIG. 4, when the second telephone signal removing unit 300 of the present invention is selected, the first telephone signal removing unit 100 and the second telephone signal removing unit 300 of the present invention are selected. It can be seen that the telephone transmission signal (824MHz-849MHz) of 850MHz is also removed along with the 900MHz telephone transmission signal (880MHz-915MHz).

In the present invention as described above, even when the telephone network moves in different regions, it is possible to automatically search the telephone network and select an appropriate signal path, so that even if the telephone network uses different regions, it is possible to interrupt digital TV broadcasts from the telephone network. It can be received without.

1 is a block diagram of a mobile TV input filter circuit in accordance with the present invention.

2 is an operational flowchart of a mobile TV input filter circuit according to the present invention;

Figure 3 is a pass frequency characteristic diagram at the time of through pass selection of the present invention.

4 is a pass frequency characteristic diagram at the time of selecting the second telephone signal removing unit of the present invention.

Explanation of symbols on the main parts of the drawings

100: first telephone signal removing unit 200: first switch

300: second telephone signal removing unit 400: through pass

500: second switch 600: telephone network search unit

700: switching control unit

Claims (6)

A first telephone signal removing unit for removing the first telephone transmission signal; A first switch connecting an output terminal of the first telephone signal removing unit to one of a first pass terminal and a first removing terminal; A second telephone signal removing unit connected to a first removing end of the first switch and removing a second telephone transmission signal from a signal through the first removing end; A through pass connected to a first pass end of the first switch and transmitting a signal through the first pass end; And A second switch connecting one of a second removing end connected to the second telephone signal removing unit and a second pass end connected to the through path to an output terminal; Mobile TV input filter circuit comprising a. The method of claim 1, wherein each of the first switch and the second switch And one signal path selected from the second telephone signal canceller and the through pass according to a switching control signal. The method of claim 2, A telephone network searching unit searching for a telephone network in service based on the telephone reception signal; And Switching control unit for supplying the switching control signal according to the search results of the telephone network search unit to the first and second switches Mobile TV input filter circuit further comprising. A first telephone signal removing unit for removing a GSM 900 MHz telephone transmission signal; A first switch connecting an output terminal of the first telephone signal removing unit to one of a first pass terminal and a first removing terminal; A second telephone signal removing unit connected to a first removing end of the first switch and removing a GSM 850 MHz telephone transmission signal from a signal through the first removing end; A through pass connected to a first pass end of the first switch and transmitting a signal through the first pass end; And A second switch connecting one of a second removing end connected to the second telephone signal removing unit and a second pass end connected to the through path to an output terminal; Mobile TV input filter circuit comprising a. The method of claim 4, wherein each of the first switch and the second switch And one signal path selected from the second telephone signal canceller and the through pass according to a switching control signal. The method of claim 5, A telephone network search unit for searching whether the service telephone network is GSM 900 or GSM850 based on the telephone reception signal; And According to a search result of the telephone network search unit, the GSM 900 telephone network to control the selection of the through pass, and if the GSM 850 telephone network switching control signal for controlling the selection of the second telephone signal removing unit to the first and second switches Switching control unit Mobile TV input filter circuit further comprising.

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