KR20080015285A - Digital multimedia broadcasting receiver and reception method thereby - Google Patents

Abstract

A DMB(Digital Multimedia Broadcasting) signal receiving apparatus is provided to select an antenna receiving the optimum DMB signal among a plurality of antennas according to intensity of an electric wave, thereby supplying a high-quality broadcasting signal to a user. A first antenna(111) and a second antenna(112) receive electric waves containing DMB signals, respectively. The first antenna has a higher gain than the second antenna. A control signal supply unit supplies a switching control signal for selectively outputting the DMB signal received through the first antenna or the second antenna, according to gain intensity of the electric wave received from the first antenna. A selector(114) selectively outputs the DMB signal received through the first antenna or the second antenna in response to the switching control signal.

Description

DM receiver and receiving method {Digital Multimedia Broadcasting Receiver And Reception Method Thereby}

1 is a block diagram showing the configuration of a DMB signal receiving apparatus according to an embodiment of the present invention.

2 is a flowchart illustrating a method of receiving a DMB signal according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100: DMB signal receiver 110: receiver

111: first antenna 112: second antenna

113: AGC driver 114: selector

120: data processing unit 130: display unit

The present invention relates to a receiving apparatus and a receiving method for receiving a DMB signal. The present invention relates to a receiving apparatus and a receiving method for a DMB signal for adjusting the received DMB signal to an appropriate intensity according to the electric field strength of the receiving area.

In general, DMB (Digital Multimedia Broadcasting) refers to digital multimedia broadcasting that can transmit not only a simple audio service such as AM broadcasting or FM broadcasting but also high-quality voice of compact disk level as well as text graphic video. Although terrestrial broadcasting generally refers to terrestrial broadcasting that provides free broadcasting locally, satellite DMB, which uses multimedia and terrestrial networks to provide multimedia pay broadcasting, is also included in the category of DMB.

Mobile Multimedia Broadcasting (hereinafter referred to as DMB) first started from DAB (Digital Audio Broadcasting, hereinafter referred to as DAB). DAB was the unique name of the Eureka-147 joint project, which was formed in Europe since 1987, and was a digital audio broadcast capable of providing high quality audio services on mobile reception. In 1993, ITU-R named DAB under the unique name of Eureka-147 (EUropean REserch Coordination Agency project-147), and the main purpose of the initial development system was audio and data broadcasting for the purpose of mobile vehicle reception. The DAB specification was completed in February 1995, and the world's first DAB broadcasting began in September 1995 at the BBC in the UK. As such, the DMB started from the DAB can be largely classified into a satellite DMB and a terrestrial DMB. Of these, DMB related to the present invention is terrestrial DMB.

Terrestrial DMB technologies include the In-Band On-Channel (IBOC) method in the United States, the Eureka-147 method in Europe, and the ISDB-TSB method in Japan. The method adopted by Korea is the European Eureka-147 method. In order to reliably transmit video service signal through the mode data channel, MPEG-2 TS (Transport Stream) is used, and H.264 video coding and BSAC audio coding, which are multimedia compression technologies, are applied to the upper layer. Thus, terrestrial DMB has a stable video service providing function in all service functions of European DAB system. The basic transmission scheme uses a differential quadrature phase shift keying (DQPSK) modulation scheme for orthogonal frequency division multiplex (OFDM). In addition, the terrestrial DMB uses a transmission mode I suitable for a mobile multimedia service of a VHF (Very High Frequency) channel among four transmission modes of the DAB.

In addition, it is an audio broadcasting form that is completely different from the existing analog sound source processing method and modulation method. For the main broadcast, the digital processing of the sound source and the modulation method also adopt a digital modulation method that is resistant to degradation or noise. The audio processing method adopts MPEG I (Moving Picture Experts Group I) Layer 2 audio compression method that compresses huge data for transmission and storage.Modulation method is coded orthogonal frequency division multiplexing with excellent moving object reception. Orthogonal Coded Frequency Division Multiplexing) is adopted.

The frequency of the DMB is about 174-240 MHz in the band-III and about 1452 ~ 1492 MHz in the L band. For example, if the antenna is implemented using a wavelength of λ / 4 of 200 MHz, the length of the antenna is about 37 cm. Should be enough. Conventional DMB antennas used in this case correspond to antennas capable of receiving analog and digital TVs in VHF / UHF (Ultra High Frequency) bands in vehicles and indoors. In addition, the general DMB antenna is a structure in which a half-wave dipole antenna is modified, and a miniaturized structure is realized by implementing a radiator of a dipole antenna in a stripline and folding the dipole antenna.

In such a conventional antenna, in order to increase the reception rate, most amplifiers are additionally provided. However, such an amplifier amplifies weak waves in the weak electric field to increase the reception rate, but in the strong electric field, there is a problem that amplifies the strong waves further, thus adversely affecting the reception rate of the DMB broadcast.

The present invention has been made to solve the above problems according to the prior art, and includes a plurality of antennas to measure the intensity of radio waves received through a high gain antenna among them, and according to the measured intensity of the radio waves An object of the present invention is to provide a DMB signal receiving apparatus and a receiving method capable of providing a user with a high quality broadcasting signal by switching an antenna capable of receiving an optimal DMB broadcasting signal among the antennas.

DMB signal receiving apparatus according to the present invention, the second antenna for receiving a radio wave containing a DMB signal; A first antenna which receives a radio wave including a DMB signal together with the second antenna and has a higher gain than the above-described second antenna; Control signal providing means for providing a switching control signal for selectively outputting the DMB signal received through the above-described first or second antenna according to the gain strength (intensity) of the radio wave received from the first antenna; And a selector for selectively outputting the DMB signal received through the first antenna or the second antenna according to the switching control signal provided from the control signal providing means.

Here, the first antenna may include, for example, a dipole antenna for receiving a radio wave including a DMB signal; And an amplifier which amplifies the radio wave received by the dipole antenna and provides a higher gain than the above-described second antenna.

In this case, it is preferable that the amplifier described above is configured as a passive type having an impedance matching and filtering function, for example.

On the other hand, the above-described control signal providing means may be configured, for example, AGC driver for providing a switching control signal as the gain strength of the radio wave received by the above-described first antenna exceeds the set gain strength.

On the other hand, the DMB signal receiving method according to the present invention includes a radio wave reception step of receiving a radio wave including the DMB signal through the first and second antennas having different gains; Switching control for selectively outputting the DMB signal received through the first or second antenna according to the gain strength (intensity) of the radio wave received from the first antenna having a higher gain than the above-described second antenna A control signal providing step of providing a signal; And a DMB signal output step of selectively outputting the DMB signal received through the first antenna or the second antenna according to the generated switching control signal.

Here, the above-described control signal providing step may include, for example, an intensity measuring step of measuring a gain intensity of a radio wave received from the aforementioned first antenna; A judging step of judging whether the gain intensity of the radio wave measured in this intensity measuring step exceeds the set gain intensity; If the strength of the radio wave determined by the determination step exceeds the set gain intensity, the switching control signal connected to the second antenna is applied. If the determined intensity of the radio wave falls below the set intensity, the radio wave is connected to the above-described first antenna. And a control signal applying step of applying a switching control signal.

Hereinafter, a DMB signal receiving apparatus according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of the DMB signal receiving apparatus according to an embodiment of the present invention. Here, the DMB signal, which will be described later, will be described as an example of applying a terrestrial DMB signal.

Referring to FIG. 1, the apparatus 100 for receiving DMB signals according to an embodiment of the present invention may include a receiver 110, a data processor 120, a display 130, and a power supply 140.

The data processor 120 decodes the digital broadcast signal received through the receiver 110 using a predetermined codec.

The display 130 outputs a video, which is a result of decoding by the data processor 120, to the user.

The power supply unit 140 supplies power necessary for the receiver 110, the data processor 120, the display 130, and the like.

Here, the above-described receiver 110 is the most essential component of the present invention. The receiver 110 includes first and second antennas 111 and 112, a selector 114, and an AGC driver 113 (Automatic Gain Controller Driver) as shown in FIG. 1.

In this case, the first antenna 111 is an antenna having an amplification function, and the second antenna 112 is an antenna having no amplification function. The selector 114 is connected to the first and second antennas 111 and 112, respectively, and performs a function of selectively operating the first or second antennas 111 and 112. Finally, the AGC driver 113 performs a function of applying the operation signal of the second antenna 112 to the selector 114 when a strong radio wave is input from the first antenna 111.

The operation of the antenna 111 of the DMB signal receiving apparatus 100 including such components is summarized as follows. The DMB signal receiving apparatus 100 including the DMB receiving antenna shown in FIG. 1 receives a radio wave including a DMB signal through the first antenna 111 in an area having a characteristic of a weak electric field. At this time, the AGC driver 113 continuously measures the gain intensity of the radio wave received through the first antenna 111.

If the DMB signal receiving apparatus 100 enters a strong electric field such as near a transmitting station, the AGC driver 113 of the receiving unit 110 may set a predetermined gain intensity (reference value) in which the measured gain intensity (strength) of the radio wave is set. Detect excess. At this time, the AGC driver 113 applies a control signal for commanding the operation of the second antenna 112 to the selector 114. That is, the AGC driver 113 is a control signal providing means for providing a control signal necessary for the operation of the selector 114.

The selector 114 controls the radio wave received through the first antenna 111 to be applied to the data processor 120 of the DMB signal receiving apparatus 100 in the region of the weak electric field. However, when the DMB signal receiver enters the strong electric field and receives the operation control signal of the second antenna 112 from the AGC driver 113, the selector 114 receives the signal from the first antenna 111. At the same time, the control unit 120 blocks the application of the signal to the data processor 120.

In this case, the second antenna 112 does not amplify the signal received by the strong electric field since there is no signal amplification function. Therefore, the data processor 120 may output a signal without an overload by the second antenna 112. That is, the data processor 120 may stably output the signal as the non-amplified signal is applied from the second antenna 112.

In conclusion, the DMB signal receiving apparatus according to the embodiment of the present invention outputs an amplified DMB signal applied from the first antenna 111 in the general weak field and applies from the second antenna 112 in the strong field. Outputs an unamplified DMB signal. That is, the DMB signal receiving apparatus according to the embodiment of the present invention outputs a DMB signal having a suitable strength according to the electric field strength of the receiving area. Therefore, the user can watch the DMB broadcast stably regardless of the reception area.

On the other hand, in the above description, the second antenna 112 described above has been described only the antenna that the amplifier function is prevented, but unlike the description may be configured to enable a slight amplification. That is, the second antenna 112 may further include an amplifier having weak amplifier capability. In this case, the amplification performance of the second antenna 112 should be weaker than the amplification performance of the above-described first antenna 111 so that the DMB signal can be output at an appropriate intensity in the weak field region.

The amplification performance of the second antenna 112 is preferably configured to have a ratio of 1: 0.1 to 0.6 with respect to the amplification performance of the first antenna 111. That is, the ratio of the amplification performance of the first antenna 111 to the amplification performance of the second antenna 112 is preferably 1: 0.1 to 0.6.

On the other hand, in the above description, unlike the above-described AGC driver 113, when a strong radio wave is input from the second antenna 112, the AGC driver 113 applies the operation signal of the second antenna 112 to the selector 114. It can be configured to perform the function. That is, the AGC driver 113 selects 114 a switching control signal for outputting the DMB signal received through the second antenna 112 according to the gain strength (strength) of the radio wave received by the second antenna 112. Can be configured to provide

On the other hand, the configuration and operation of each element of the above-described receiver 110 will be described in more detail as follows.

The first antenna 111 and the second antenna 112 include a dipole antenna and the like to receive radio waves existing in the air. Of course, the first and second antennas 111 and 112 are not limited to dipole antennas.

The radio wave received through the dipole antenna of the first antenna 111 is applied to a circuit for increasing the gain. As described above, the circuit for increasing gain may be configured as an amplifier circuit using a plurality of resistors, inductors, capacitors, and transistors.

Such an amplification circuit corresponds to a kind of amplifier, which is easily understood by those skilled in the art, and thus a detailed description thereof will be omitted. In particular, the first antenna 111 may apply an active type circuit to increase the gain. However, if a sufficient gain can be secured using a passive type circuit, a passive type circuit in which impedance matching and filtering functions are added may be adopted. The passive type circuit to which such a function is added can be easily understood by those skilled in the art, and thus a detailed description thereof will be omitted.

The radio wave amplified by the aforementioned first antenna 111 is applied to the AGC driver 113 and transmitted to the selector 114 as described above. As such, the reason why the signal is applied to the AGC driver 113 is to detect the gain strength of the currently received signal as described above.

On the other hand, since the second antenna 112 has no amplification function as described above, the second antenna 112 has a lower gain characteristic than the first antenna 111. As such, in order to secure a low gain characteristic, it is preferable that the second antenna 112 use a general passive type circuit. Of course, the second antenna 112 may further employ a circuit that performs impedance matching and filtering functions like the first antenna 111 in order to further improve the DMB reception rate.

The received signal input through the dipole antenna of the second antenna 112 is directly applied to the selector 114 without any amplification process.

On the other hand, the AGC driver 113 shown in FIG. 1 will be described in detail as follows. AGC (Auto Gain Control) refers to a device that detects the amplitude variation of a wireless receiver or amplifier input signal and automatically adjusts the gain so that the amplitude of the output signal is always constant. The AGC lowers the gain strength by using reverse bias when a gain higher than the set gain intensity is input, and increases the gain strength by using forward bias when a gain lower than the set gain intensity is input. Thus, the AGC keeps the amplitude of the output signal constant at all times.

However, the AGC driver 113 in the present invention detects the amplitude variation of the input signal and notifies the selector 114, rather than the function of always keeping the amplitude constant. That is, the AGC driver 113 applied to the present invention is not used to automatically adjust the gain, but is used to provide a switching control signal which is an operation signal of the selector 114.

In particular, the AGC driver 113 applied to the present invention, when the detected gain intensity is greater than the set gain intensity, the current which operates the selector 114 without generating a reverse bias which lowers this gain intensity below the set intensity. To produce. Thus, the AGC driver 113 operates the selector 114 in accordance with the gain strength detected.

Here, the aforementioned AGC driver 113 may include a BAS40-07 device including two diodes. The BAS40-07 device is a type of Schottky Barrier Diode.

Using the diode device, the AGC driver 113 may determine whether the intensity of the current signal received by the first antenna 111 exceeds a predetermined reference value. The determination result may be applied to the selector 114 via an operational amplifier or the like.

The selector 114 receives a control command signal from the AGC driver 113 and an amplified signal and an unamplified signal from the first and second antennas 111 and 112, respectively. The selector 114 transmits a signal of the first antenna 111 to the output unit in a normal case in which the control command signal is not applied from the AGC driver 113. When the control command signal is received from the AGC driver 113, an operation of outputting the signal transmitted from the second antenna 112 is performed. That is, the selector 114 performs the same function as the variable switch according to the control command signal of the AGC driver 113.

Here, the selector 114 described above may be configured using a multiplexer, or may be configured through an element such as a transistor that performs a switch function.

Meanwhile, FIG. 2 is a flowchart illustrating a method for receiving a DMB signal according to an embodiment of the present invention. Referring to FIG. 2, the method for receiving a DMB signal according to an embodiment of the present invention will be described below. . At this time, the DMB signal receiving method according to an embodiment of the present invention will be described as an example implemented through the above-described DMB signal receiving apparatus 100.

2, in the method for receiving a DMB signal according to an embodiment of the present invention, the DMB signal is received through the first and second antennas 111 and 112 of the above-described DMB signal receiving apparatus 100 (S201, S202). That is, the DMB signal receiving apparatus 100 is a diversity type system.

In this case, the first antenna 111 may amplify the DMB signal as described above (S201). The second antenna 112 may not amplify the DMB signal as described above (S202).

The DMB signal receiving apparatus 100 performs a function of outputting a DMB broadcast to a user by using the broadcast signal of the first antenna 111 at normal time (S203). That is, the DMB signal receiving apparatus 100 usually outputs an amplified DMB signal so that the reception rate is high.

At this time, the DMB signal receiving apparatus 100 senses the strength of the radio wave received through the first antenna 111, that is, the gain strength (S204), so that the DMB signal receiving apparatus 100 exists in the region of the weak electric field. Determine if it exists in the area of strong electric field. In this case, the radio wave means not only a digital broadcast signal but also a radio wave of all bandwidths that the first antenna 111 can receive. This is because the electric field strength of the region to which the DMB signal receiving apparatus 100 belongs is determined by the digital broadcast signal and other radio waves.

The DMB signal receiving apparatus 100 determines that the measured intensity of the radio wave is located in the region of the strong electric field when it exceeds the set reference value. If the intensity of the radio wave is less than the set reference value, the radio wave is determined to be a region of the weak electric field (a region other than a strong electric field) (S205). If it exceeds, it is determined as the strong electric field area, and when the measured gain strength of the measured radio wave is less than the set gain intensity, it is determined as the weak electric field area. At this time, the DMB signal receiving apparatus 100 is preferably configured to determine the gain strength by using the AGC driver 113 described above.

On the other hand, when it is determined that the DMB signal receiving apparatus 100 exists in the region of the strong electric field, the DMB signal receiving apparatus 100 uses a DMB broadcast using the DMB signal applied from the second antenna 112 that is not amplified. In other words, the DMB signal receiving apparatus 100 outputs the DMB broadcast by decoding the non-amplified DMB signal.

In this case, the DMB signal receiving apparatus 100 is configured to provide DMB broadcasting to the user through the above-described selector 114 for selectively outputting the DMB signal applied from the first antenna 111 or the second antenna 112. It is preferable. Of course, the selector 114 selectively outputs the DMB signal while switching by the switching control signal of the AGC driver 113 as described above.

On the contrary, when it is determined that the DMB signal receiving apparatus 100 is located in the region of the weak electric field, the DMB receiving apparatus 100 provides a DMB broadcast using the DMB signal amplified by the first antenna 111 to the user. That is, the DMB signal receiving apparatus 100 decodes the amplified DMB signal and outputs a DMB broadcast.

When the DMB signal receiving apparatus 100 is configured as described above, the DMB signal receiving apparatus 100 measures the gain intensity of the radio wave received from the first antenna 111 through the above-described AGC driver 113. Then, the measured gain intensity is compared with the set gain intensity. Then, the selector 114 is operated through the above-described AGC driver 113 to selectively output the DMB signal of the first antenna 111 or the second antenna 112.

At this time, the AGC driver 113 compares the gain intensity of the radio wave received by the first antenna 111 and the set gain intensity to determine whether the gain intensity of the received radio wave is higher than the set gain intensity. When the gain strength of the first antenna 111 is higher than the set gain strength, the switching control signal for outputting the DMB signal received by the second antenna 112 is applied to the selector 114. On the contrary, when the gain strength of the first antenna 111 is lower than the set gain strength, the switching control signal for outputting the DMB signal received by the first antenna 111 is applied to the selector 114. Accordingly, the selector 114 selectively outputs the signals of the first or second antennas 111 and 112 according to the gain intensity of the radio wave received by the first antenna 111. Of course, the DMB signal receiving apparatus 100 selectively decodes the DMB signal received by the first or second antennas 111 and 112 by the selector 114 selectively operated to output the DMB broadcast.

The DMB signal receiving apparatus 100 as described above may selectively use broadcast signals received by two antennas according to circumstances. Therefore, the user can smoothly watch the DMB broadcast not only in the weak electric field but also in the strong electric field.

As described above, the DMB signal receiving apparatus and the receiving method according to the present invention use only a signal having a high gain intensity when entering the region of the weak field, and use only a signal having a low gain intensity when entering the region of the strong field. The reception rate of the DMB broadcast signal can be increased, and in addition, an error does not occur in decoding, thereby providing a DMB broadcast service of higher quality to the user. In addition, by using an existing device such as AGC, there is an advantage that can provide a user with a DMB signal receiving device that can receive the DMB signal stably at a lower price.

On the other hand, since the above description is only a description of a preferred preferred embodiment of the present invention can be variously changed within the scope of the same idea. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the claims below but also by the equivalents of the claims.

Claims (6)

In the DMB signal receiving apparatus, A second antenna for receiving a radio wave including a DMB signal; A first antenna which receives a radio wave including a DMB signal together with the second antenna and has a higher gain than the second antenna; Control signal providing means for providing a switching control signal for selectively outputting a DMB signal received through the first or second antenna according to a gain intensity (wave strength) of the radio wave received from the first antenna; And And a selector for selectively outputting a DMB signal received through the first antenna or the second antenna according to a switching control signal provided from the control signal providing means. The method of claim 1, wherein the first antenna, A dipole antenna for receiving a radio wave including a DMB signal; And And an amplifier for amplifying a radio wave received by the dipole antenna to provide a higher gain than the second antenna. The method of claim 2, The amplifier has a passive type (Passive Type) having an impedance matching and filtering function. According to any one of claims 1 to 3, wherein the control signal providing means, And an AGC driver for providing a switching control signal when the gain strength of the radio wave received by the first antenna exceeds a set gain strength. In the method for receiving a DMB signal, A radio wave reception step of receiving radio waves including a DMB signal through first and second antennas having different gains; Providing a switching control signal for selectively outputting the DMB signal received through the first or second antenna according to the gain strength (intensity) of the radio wave received from the first antenna having a higher gain than the second antenna Providing a control signal; And And a DMB signal output step of selectively outputting the DMB signal received through the first antenna or the second antenna according to the generated switching control signal. The method of claim 5, wherein the providing of the control signal comprises: An intensity measuring step of measuring a gain intensity of a radio wave received from the first antenna; A determination step of determining whether the gain intensity of the radio wave measured in the intensity measurement step exceeds a set gain intensity; And When the strength of the radio wave determined by the determination step exceeds the set gain intensity, a switching control signal connected to the second antenna is applied. When the determined intensity of the radio wave falls below the set intensity, the switching is connected to the first antenna. A control signal applying step of applying a control signal; DMB signal receiving method comprising a.

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