KR100265116B1 - Apparatus for swithcing rf signals with different transmission standards - Google Patents

Abstract

PURPOSE: An apparatus for switching RF signals having different standards is provided to connect different broadcasting cables to one tuner. CONSTITUTION: An RF switching section(100) is connected to broadcasting cables. The RF switching section(100) includes a switching output terminal for outputting one selected from RF signals received from the broadcasting cables. The RF switching section(100) selects and outputs one of the RF signals to the switching output terminal corresponding to a direct current level of a switching control signal overlapped to the switching output terminal. A tuner(102) includes an antenna input terminal connected to the switching output terminal of the RF switching section(100). The tuner(102) overlaps the switching control signal to the antenna input terminal. The tuner(102) demodulates the RF signal from the RF switching section(100) according to a transmission standard corresponding to a direct current level step of the switching control signal.

Description

RF signal switching device with different transmission standard {APPARATUS FOR SWITHCING RF SIGNALS WITH DIFFERENT TRANSMISSION STANDARDS}

The present invention relates to a radio frequency (RF) signal input device, and more particularly, to an apparatus for inputting an RF signal from broadcast cables transmitting one RF signal having a different transmission standard.

In the previous television (Television) receiver, the tuner (tuner) has been input and processed only the RF signal of one broadcast standard. In contrast, digital TV receivers such as HDTV (High Definition Television) have been proposed to input and process a plurality of RF signals having different transmission standards. In this case, a plurality of broadcast cables for transmitting one RF signal each having a different transmission standard are connected to one tuner. The transmission standard may be various, such as the National Television System Committe (NTSC) standard, the HDTV standard, or the Digital Broadcasting Satellite (DBS) standard.

In this case, the tuner requires an RF signal switching device that can be used by connecting broadcast cables to one tuner. As such, when a plurality of RF signal inputs are required, a dedicated device such as a cable decoder may be added separately to switch the RF signal.

As described above, when a plurality of broadcast cables having different transmission standards are connected to one tuner, a separate dedicated device has to be additionally used for RF signal switching. Accordingly, there is a disadvantage that the configuration of the device is complicated and the cost is increased.

Accordingly, an object of the present invention is to provide an RF signal switching device capable of simply connecting broadcast cables having different transmission standards to one tuner.

1 is a circuit diagram of an RF signal switching device according to a first embodiment of the present invention;

2 is a circuit diagram of an RF signal switching device according to a second embodiment of the present invention.

In order to achieve the above object, the present invention provides a tuner unit for converting a control signal for selecting one of the RF signals received from broadcast cables for transmitting one RF signal each having a different transmission standard to a direct current level. Superimposed on the antenna input terminal, selects and inputs and demodulates an RF signal corresponding to the DC level.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the annexed drawings, numerous specific details are set forth in order to provide a more thorough understanding of the present invention, such as specific circuit configurations, types or number of elements or components, and the like. It will be apparent to those skilled in the art that the present invention may be practiced without these specific details. And a detailed description of known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted. In addition, it should be noted that in the following description, the same components in the drawings represent the same reference signs wherever possible.

1 is a circuit diagram of a switching device according to a first embodiment of the present invention, in which an RF signal is input from two broadcasting cables (not shown), each transmitting two RF signals having different transmission standards. The configuration example in the case is shown. In FIG. 1, the RF switching unit 100 switches one of the first and second RF signals input through the first and second input terminals 104 and 106 connected to the broadcast cables of different transmission standards, respectively, one by one. ) Is selected to correspond to the DC level of the switching control signal superimposed on the < RTI ID = 0.0 >) < / RTI > The tuner unit 102 superimposes the switching control signal on the antenna input terminal 110 connected by the cable 118 to the switching output terminal 108 of the RF switching unit 100 and is output from the RF switching unit 100. One of the RF signals is demodulated according to a transmission standard corresponding to the DC level of the switching control signal.

The RF switching unit 100 includes first and second input terminals 104 and 106, first and second capacitors C1 and C2, a first switch SW1, and a switching output terminal 108. Looking in more detail as follows. The first and second input terminals 104 and 106 are respectively connected to two broadcast cables having different transmission standards. Therefore, first and second RF signals are input to the first and second input terminals 104 and 106 from two broadcast cables, respectively. The first and second input terminals 104 and 106 are connected to the first switch SW1 via the first and second capacitors C1 and C2, respectively. In the first switch SW1, two input terminals Pi1 and Pi2 are connected to the first and second input terminals 104 and 106 through the first and second capacitors C1 and C2, respectively, and one output terminal is provided. The Po and the control terminal Pc are commonly connected to the switching output terminal 108. The first switch SW1 is switched corresponding to the DC level of the switching control signal superimposed on the switching output terminal 108 to output one of the first and second RF signals to the switching output terminal 108.

The tuner unit 102 includes an antenna input terminal 110, a third capacitor C3, a second switch SW2, first and second broadcast demodulators 114 and 116, a diode D1, and a control input terminal 112. ), Which is described in more detail as follows. The antenna input terminal 110 is connected to the switching output terminal 108 of the RF switching unit 100 through a cable 118, and is connected to the second switch SW2 via a third capacitor C3. The second switch SW2 has one input terminal Pi connected to the antenna input terminal 110 through the third capacitor C3 and two output terminals Po1 and Po2 connected to the first and second broadcast demodulators. One control terminal Pc is connected to the input terminals 114 and 116, respectively, and one control terminal Pc is connected to the control input terminal 112. The second switch SW2 switches the first RF signal or the second RF signal input to the antenna input terminal 110 to correspond to the DC level of the switching control signal so that the second switch SW2 is connected to one of the first and second broadcast demodulators 114 and 116. Is authorized. The first and second broadcast demodulators 114 and 116 demodulate the first and second RF signals one by one according to a corresponding transmission standard. Therefore, the first broadcast demodulator 114 demodulates the first RF signal and outputs the first demodulated output when the first RF signal is input from the second switch SW2, and the second broadcast demodulator 116 outputs the second switch. When the second RF signal is input from SW2, the second RF signal is demodulated and output to the second demodulation output. The diode D1 is connected between the antenna input terminal 110 and the control input terminal 112. The cathode of the diode D1 is connected to the antenna input terminal 110, and the diode D1 is connected to the control input terminal 112. ) Anode is connected.

The switching control signal has a DC level corresponding to one RF signal to be input among the first and second DC levels corresponding to each of the first and second RF signals. That is, when the first RF signal is to be selected and inputted, the switching control signal has a first DC level, and when the second RF signal is selected and inputted, the switching control signal has a second DC level. For example, the first DC level is a "high" level by the power supply voltage Vcc, and the second DC level is a "low" level by ground. The switching control signal may be generated according to the type of RF signal to be input by the control unit of the apparatus such as the digital TV receiver having FIG. 1.

The first switch SW1 is switched by a switching control signal superimposed on the signal line by the diode D1 of the tuner unit 102, and the second switch SW2 is also linked thereto. At this time, the DC level of the overlapping switching control signal is blocked by the first and second capacitors C1 and C2 so as not to be applied to the first and second input terminals 104 and 106 and is not applied to the second switch SW2. It is blocked by the third capacitor C3.

In the above state, broadcast cables of different transmission standards are connected to the first and second input terminals 104 and 106 of the RF switching unit 100, and the first and second RF signals transmitted one by one from each broadcast cable are respectively made. It is applied to the first switch SW1 through the first and second capacitors C1 and C2. Then, the first switch SW1 is switched corresponding to the DC level of the switching control signal superimposed on the signal line connected to the switching output terminal 108 to output one of the first and second RF signals. The RF signal selected by the first switch SW1 is applied to the second switch SW2 via the switching output terminal 108, the cable 118, the antenna input terminal 110, and the third capacitor C3. . Then, the second switch SW2 switches the RF signal input by switching in conjunction with the first switch SW1 to correspond to the DC level of the switching control signal input through the control input terminal 112. To one of the grandparents 114, 116. Accordingly, one RF signal to be input among the first and second RF signals is selected by the first switch SW1 and input to the tuner unit 102, and the tuner unit 102 first and second broadcast demodulators 114 and 116. In the meantime, the second switch SW2 is applied to the broadcast demodulation unit conforming to the transmission standard of the RF signal, and is then demodulated and output.

Here, assuming that the first RF signal is a digital broadcast RF signal transmitted through a digital broadcast cable and the second RF signal is a cable broadcast RF signal transmitted through a cable broadcast cable, the first broadcast demodulator 114 uses the digital broadcast demodulator. The second broadcast demodulator 116 uses a cable broadcast demodulator. If the DC level of the switching control signal is set to "high" level when the first RF signal, which is a digital broadcasting RF signal, is set to "low" level when the second RF signal, which is a cable broadcasting RF signal, is input, The first and second switches SW1 and SW2 are as follows. That is, when the signal applied to the control terminal Pc is at the "high" level, the first switch SW1 outputs the signal input to the input terminal Pi1 to the output terminal Po and is at the "low" level. In the switch, a switch for outputting a signal input to the input terminal Pi2 to the output terminal Po is used. When the signal applied to the control terminal Pc is at the "high" level, the second switch SW2 outputs the signal input to the input terminal Pi to the output terminal Po1 and is at the "low" level. A switch for outputting the signal input to the input terminal Pi to the output terminal Po2 is used. Then, any one of the first and second RF signals is input to the tuner unit 102 and demodulated in the corresponding one of the first and second broadcast demodulators 114 and 116 and then output.

Therefore, two broadcasting cables with different transmission specifications can be connected to one tuner without additional equipment such as a cable decoder.

FIG. 2 is a circuit diagram of a switching device according to a second embodiment of the present invention. In the tuner unit 102 of FIG. 1, the second switch SW2 is connected to the third capacitor C3 and the first and second broadcast signals. Unlike the ones installed between the grand units 114 and 116, the tuner unit 120 is configured by being installed at the output terminals of the first and second broadcast demodulators 114 and 116. Therefore, the RF switching unit 100 is the same as in FIG. 1, and in the tuner unit 120, only the type and the installation position of the second switch SW2 are changed, and the rest of the configuration is the same as in FIG. 1.

2, the tuner 120 demodulates the RF signal output from the RF switcher 100 according to the transmission standard of the first and second RF signals, and then controls one of the demodulation outputs. The output is selected according to the DC level of the signal. Looking at the tuner unit 120 in more detail, the antenna input terminal 110 is connected to the switching output terminal 108 of the RF switching unit 100 through a cable 118, and through the third capacitor (C3) Commonly connected to the input terminals of the first and second broadcast demodulators 114 and 116. The first and second broadcast demodulators 114 and 116 demodulate the RF signals input through the third capacitor C3 according to the transmission specifications of the first and second RF signals, respectively. The second switch SW2 is connected to the output terminals of the first and second broadcast demodulators 114 and 116 and the control input terminal 112. In the second switch SW2, two input terminals Pi1 and Pi2 are connected to the first and second broadcast demodulators 114 and 116, respectively, and one output terminal Po is connected to the final output terminal of the tuner unit 120. One control terminal Pc is connected to the control input terminal 112. The second switch SW2 is switched corresponding to the DC level of the switching control signal to output one of the demodulation outputs of the first and second broadcast demodulators 114 and 116. A diode D1 is connected between the antenna input terminal 110 and the control input terminal 112 as in FIG. 1.

When the tuner unit 120 is configured as shown in FIG. 2, only one demodulated output demodulated in accordance with the transmission standard of the RF signal selected and output from the RF switching unit 100 among the first and second RF signals may include a second switch ( Output from SW2). Therefore, unlike in FIG. 1, since the output terminal of the tuner 120 is one, the configuration of the side to which the demodulation output is applied can be simplified compared to FIG. 1.

Meanwhile, in the above description of the present invention, specific embodiments have been described, but various modifications can be made without departing from the scope of the present invention. In particular, the embodiment of the present invention has shown an example of switching between two RF signals, it can be applied to a plurality of RF signals in the same manner. In this case, the DC level of the switching control signal is generated by dividing it into the number of stages of the RF signal, and the first and second switches SW1 and SW2 are switched in multiple stages to correspond to the DC level of the switching control signal. A switch is used, and the RF switching unit 100 may use as many input terminals and capacitors as RF signals. Therefore, the scope of the invention should not be defined by the described embodiments, but should be defined by the equivalent of claims and claims.

As described above, when a plurality of RF signal inputs are required, the present invention can be used by simply connecting a plurality of broadcast cables having different transmission standards to one tuner without separately adding another device such as a cable decoder. There is an advantage.

Claims (3)

In the apparatus for inputting the RF signal from at least two broadcast cables for transmitting each one of a different RF signal transmission standard, The RF signals connected to the broadcast cables and having a switching output terminal for outputting a selected one of the RF signals received from the broadcasting cables, and corresponding to the DC level of the switching control signal superimposed on the switching output terminal; RF switching unit for selecting one of the output to the output terminal, The switching control signal having an antenna input terminal connected to the switching output terminal of the RF switching unit, and having a DC level of a step corresponding to one RF signal to be input among DC level steps corresponding to each one of the RF signals. An RF signal switching having a different transmission standard, the tuner unit being superimposed on the antenna input terminal and demodulating the RF signal output from the RF switching unit according to a transmission standard corresponding to the DC level of the switching control signal; Device. In the apparatus for inputting the RF signal from the two broadcast cables for transmitting one each of the first and second RF signals of different transmission standards, A switching output terminal for outputting a selected one of first and second RF signals connected to the broadcasting cables and received from the broadcasting cables, and corresponding to a DC level of a switching control signal superimposed on the switching output terminal; An RF switching unit for selecting one of the first and second RF signals and outputting the switching output terminal to the switching output terminal; An antenna input terminal connected to the switching output terminal of the RF switching unit, and having a DC level corresponding to one RF signal to be input among first and second DC levels corresponding to each of the first and second RF signals; And a tuner unit for superimposing a switching control signal on the antenna input terminal and demodulating the RF signal output from the RF switching unit according to a transmission standard corresponding to the DC level of the switching control signal. RF signal switching device. The method of claim 2, wherein the RF switching unit, First and second input terminals connected to each of the two broadcast cables, one for inputting the first and second RF signals, respectively; The switching output terminal, First and second capacitors are connected to the first and second input terminals, respectively, and are connected to the switching output terminal and switched corresponding to the DC level of the switching control signal appearing at the switching output terminal. And a first switch for outputting one of 2RF signals to the switching output terminal.

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