JP2008054009A - Receiving antenna for digital broadcasting and digital broadcast receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a broadcast receiving antenna which is incorporated in a thin-screen broadcast receiver and shares a speaker part with a metallic waveguide antenna part. <P>SOLUTION: A magnetic current induction broadcast receiving antenna includes: a metallic waveguide 10 having a rectangular aperture face 17; a sound reproducer 12 disposed in a short-circuited end surface 11 of the metallic waveguide 10, which faces the aperture face; a sound adjustment mechanism 13 consisting of a pair of dielectric plates forming a horn expanding toward the aperture face 17 from the sound reproducer 12, together with waveguide side walls, in order to use the inside of the waveguide 10 as a sound wave passage; and a sound wave reflecting plate 15 which faces the short-circuited end surface 11 of the waveguide 10 and reflects a sound wave from the sound reproducer 12. The side walls of the waveguide 10 are provided with a plurality of sound wave passage holes 16 through which the sound wave from the sound wave reflecting plate 15 passes, the sound wave radiated from the sound reproducer 12 is reflected by the sound wave reflecting plate 15, and the reflected sound wave is propagated through the sound wave passage holes 16. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a digital broadcast receiving antenna and a digital broadcast receiver, and more particularly, to receive a digital broadcast in a free arrangement indoors and to have a small and good reception characteristic for a digital broadcast and a digital broadcast. It relates to a receiver.

  Conventionally, in analog broadcasting, when receiving a broadcast electric wave with a weak electric field, a decrease in reception level of several dB greatly affects the image quality, or when receiving a radio wave in an urban area, an unpleasant ghost due to a reflected wave from a building. Since an image is generated, it is necessary to install and use an antenna having a high gain in the direction of incoming radio waves and a low gain in the direction of reflected radio waves in a position where the incoming radio waves are as strong as possible. Therefore, as a conventional antenna installation method, a method in which an antenna having directivity in the horizontal direction is supported by a metal column and installed at a high position on the roof has been adopted.

  Further, on the transmitting side that transmits the broadcast wave of the analog broadcast, horizontal polarization has been adopted as the polarization direction of the broadcast wave. This is because when the horizontal polarization is received by the antenna on the receiving side, the decrease in the reception level caused by the disturbance of the received electric field caused by the current induced in the metal pillar of the antenna is small, and the horizontal polarization is also received on the transmission side. This is because a non-directional transmission antenna is realized in the horizontal direction.

  And, as an antenna on the analog broadcast wave receiving side, the resistance to wind is small, the equivalent reception area of the antenna is large, that is, the reception band is wide, and the gain can be increased easily by increasing the number of elements. Conventionally, a current-induced dipole antenna has been used.

  In addition, it is possible to receive broadcast waves of the analog broadcast by an indoor antenna that does not require antenna wiring from the wall to the receiver, regardless of the outdoor antenna as described above. , A current-induced dipole antenna is exclusively used since it has a wide reception band and can be realized at a low cost with a simple configuration (see, for example, Patent Document 1).

  On the other hand, in digital broadcasting that has been spreading in recent years, in the case of receiving a broadcast wave with a relatively strong electric field in urban areas, even if there is a reflected wave from a building, the principle is different from the analog broadcast. Since no ghost image is generated, attention is paid to the usefulness of the indoor antenna that does not require antenna wiring from the wall as an antenna for receiving the broadcast of the digital broadcast.

  On the user side, digital broadcasting is characterized in that there is no deterioration in image quality unless the reception level of radio waves is below a threshold value. From this point, the indoor antenna has the advantage that the receiver can be freely carried indoors and placed. Therefore, even when receiving a broadcast electric wave with a weak electric field more than analog broadcasting, the indoor antenna can perform digital broadcasting. There has been a demand for receiving broadcast radio waves, and its realization has been expected.

  Further, even with analog broadcast receiving antennas that are already widely used, broadcasting with horizontally polarized waves is preferable so that digital broadcast radio waves can be received. Those capable of receiving polarized waves are preferred.

  Based on the above, an antenna using a magnetic current induced in an opening provided in a metal plate or metal box as a radiation source (hereinafter referred to as a “magnetic current induction type antenna”) is used for a conventional indoor antenna. Compared with the current-induced antenna, the installation area is small because it can receive horizontally polarized waves in a vertically elongated shape, and the directivity is almost omnidirectional in the horizontal direction. If it pays attention to having the characteristic that it is not necessary, this magnetic current induction type antenna is a unit antenna element of an indoor antenna for receiving a digital broadcast that can meet the requirements for the receiving antenna for a digital broadcast as described above. (See, for example, Reference 2 and Reference 3).

In recent years, in response to the popularity of thin television receivers, waveguide antennas for receiving digital broadcasts have been proposed that can be mounted or incorporated without significantly reducing the thinness that is characteristic of the television receiver. (Refer literature 4).
Japanese Utility Model Publication No. 5-80014 JP 58-15303 A JP 2003-1224738 A JP 2005-102142 A

  However, the magnetic current induction type waveguide antenna (Reference 4: Japanese Patent Application Laid-Open No. 2005-102142) considered to be promising as a receiving antenna for digital broadcasting having the conventional configuration is 470 MHz to be used in digital broadcasting. In order to efficiently receive broadband broadcast waves over 710 MHz, the size tends to increase to some extent and cost.

  As a result, it is difficult to distribute the internal space, such as the power circuit, video signal processing unit, and audio processing unit including speakers, in order to place the waveguide antenna in the space inside the flat-screen television receiver. There are significant restrictions on the placement of the waveguide antenna.

  Furthermore, the cost increase of the television receiver by incorporating the waveguide antenna is inevitable.

  The present invention solves the above-described conventional problems, and in the case where a magnetic current induction type antenna suitable for reception of a digital broadcast broadcast in horizontal polarization is incorporated in a thin television receiver or the like, the thin television A digital built-in antenna that can be easily installed in the receiver's internal space and built into the receiver, and that provides a low-cost antenna that can share the built-in space with speakers that have particularly good sound quality, and that has better reception performance. An object is to provide a broadcast receiver.

  In order to solve the above-described conventional problems, a digital broadcast receiving antenna according to the present invention is a magnetic current induction type digital broadcast receiving antenna, which is opposed to a metal waveguide having a rectangular opening surface and the opening surface. An audio regenerator disposed on the short-circuited end surface of the metal waveguide, and a horn that expands from the sound regenerator toward the opening surface in combination with the side wall of the waveguide so that the inside of the waveguide serves as a sound wave path An acoustic adjustment mechanism comprising a pair of dielectric plates, and a sound wave reflection plate that faces the short-circuited end face of the waveguide and reflects sound waves from the sound reproducer, and the waveguide side wall includes the sound wave A plurality of sound wave passage holes through which sound waves from the reflection plate pass, the sound waves emitted from the sound reproducing device are reflected by the sound wave reflection plate, and the reflected sound waves are propagated through the sound wave passage holes; It is characterized by that That.

  The digital broadcast receiving antenna of the present invention is a magnetic current induction type digital broadcast receiving antenna, which is a metal waveguide having a rectangular opening, and a short-circuit end face of the metal waveguide facing the opening. And a pair of dielectric plates that form a horn that expands from the sound wave regenerator toward the opening surface in combination with the side wall of the wave guide to form a sound wave path in the waveguide. An acoustic adjustment mechanism, and the short-circuit surface of the waveguide has a sound wave passage hole through which a sound wave radiated from the sound reproducing device passes.

  Further, the present invention is a digital broadcast receiver, characterized in that the digital broadcast receiving antenna according to claim 2 is provided at both end portions of the receiver.

  According to the receiving antenna for digital broadcasting of the present invention, the metal waveguide has a sound wave path that is processed by sheet metal and has a sound wave path that is not sealed with a material that cuts off sound waves of a dielectric or magnetic material. One end of the short circuit and the other end are opened to form an antenna opening, an electric field short circuit and sound wave passing mechanism is provided on the waveguide surface of the short circuit end, and the sound wave path in the waveguide outside the waveguide of the short circuit end Since it has a structure equipped with a sound reproducing device (speaker) that emits sound waves, it can be easily combined with a speaker in the receiver. By acoustically adjusting the sound wave generated from this speaker in the waveguide, the waveguide antenna can be used like a dome speaker for a receiver. An antenna can be arranged, and furthermore, since the metal plate constituting the waveguide antenna and the metal plate constituting the speaker can be shared, the price can be reduced.

  Furthermore, a sound wave reflector / electric field passage mechanism that changes the propagation direction of the sound wave to the opening of the waveguide and allows the electric field to pass through, and a sound wave that causes the sound wave to radiate through the tube wall of the metal waveguide and to short-circuit the electric field. By providing the passing and electric field short-circuit mechanism and the sound reproduction function, the waveguide antenna can be incorporated in the receiver without greatly detracting from the thinness that is characteristic of the thin television receiver.

  In addition, by providing a waveguide antenna at both ends of the receiver housing and performing diversity reception using both antennas, a digital broadcast receiver capable of receiving digital broadcast waves efficiently and stably can be realized. .

  Embodiments of a digital broadcast receiving antenna and a digital broadcast receiver according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a digital broadcast receiving waveguide antenna according to Embodiment 1 of the present invention. The waveguide antenna uses the shape and side surfaces of a horn speaker or the like used for an audio player 12. 10. The antenna of the present invention has a rectangular parallelepiped metal waveguide 10 having an opening on one side, and a sound wave reflecting plate 15 made of a dielectric material for reflecting sound waves and a broadcast on the opening end 17 side of the waveguide antenna. A sound wave passage hole 16 that emits a sound wave toward the person who is watching is provided. The sound wave passage hole 16 is provided with a hole of a predetermined size in the metal waveguide 10, but the metal waveguide 10 functions as an electric field short-circuit mechanism. The sound wave emitted from the sound reproducer 12 is transmitted to the opening end 17 of the metal waveguide 10 through the sound wave adjusting mechanism 13 of the dielectric plate forming the acoustic horn, and reflected by the sound wave reflection plate 15 to pass the sound wave. The viewer is reached through the hole 16. The radio wave received at the open end 17 of the metal waveguide 10 resonates in the waveguide corresponding to the reception channel and is output to the RF connector 18.

  As shown in FIG. 1, a metal wall of the metal waveguide 10 and an acoustic adjustment plate 13 that is a sound quality adjustment mechanism constitute an acoustic horn in the waveguide. An acoustic horn is an acoustic tube with a gradually changing cross-section, and the acoustic horn wall reflects wood waves, resin, metal, etc. well to reflect sound waves in a wide band and without loss to the opening that is the outlet of the acoustic horn. It is desirable to be sealed with a plate material. When changing the direction of sound waves radiated from the opening of the acoustic horn with a reflector, it is desirable to install a reflector not in the acoustic horn but in the opening, and the reflected sound waves are radiated efficiently. Thus, even when the direction of the sound wave is changed, it is desirable to provide an opening area equivalent to the opening area of the original acoustic horn. Therefore, as shown in FIG. 1, the sound wave reflection / electric field passage mechanism 15 and the sound wave passage hole / electric field short-circuit mechanism 16 are arranged in a region near the open end 17 of the waveguide which is an antenna opening and an opening portion of the acoustic horn. It is desirable to provide in the area | region which has the width | variety equivalent to the thickness of the metal waveguide 10 which is the opening area of this acoustic horn.

  Further, the hole 16 which is a sound wave passage hole and electric field short-circuit mechanism is 2 cm which is less than 1/20 of the wavelength 42 cm of the maximum frequency 710 MHz of the broadcast frequency so that the electric field can be efficiently short-circuited with respect to the wavelength of the television broadcast frequency band. The following is desirable, and it is desirable to arrange the holes at a density such that the ratio of the opening area is at least 50% or more so that sound waves can be efficiently emitted into the space as the opening of the acoustic horn.

Next, a general operation of the aperture waveguide will be described with reference to FIG.
In addition, the same number is used for the same structure and the same function shown in FIG.
As shown in FIG. 2A, a magnetic current H21 associated with an electric field E22 appearing at the open end 17 of the waveguide is used as a radiation source to be used as an antenna. And when the opening width W25 of the general waveguide is set to ½ wavelength or more of the use frequency, the waveguide length L29 is ¼ wavelength of the in-tube wavelength when one side is short-circuited and the other is opened. When both sides are open, they are used by resonating at a half wavelength of the guide wavelength. In order to reduce the cost of such an open waveguide, the open waveguide of the present application is made of the same metal plate.

  FIG. 2B schematically shows the configuration of a metal waveguide antenna in order to explain the principle of operation of the magnetic current excitation type antenna. First, the input impedance of the waveguide antenna 10 will be described. In the waveguide antenna resonating at a certain frequency, since the electric field E22 generated so as to wind the magnetic current H21 generated at the open end 17 enters the waveguide outer wall perpendicularly, the radiation electric field is generated by the waveguide outer wall. Thus, the radiation pattern is almost the same as that of the electric dipole antenna 27 which is not disturbed and thus is simply replaced by the electric field E22 and the magnetic field H21. That is, since the waveguide antenna 10 can be regarded as a slot antenna having a complementary relationship with the electric dipole antenna 27, it can be used as a television broadcast receiving antenna.

From the principle of Babinet, between the input impedance Zm at the open end 17 of the waveguide antenna and the input impedance Zj of the electric dipole antenna 27,
There is a relationship of Zm · Zj = (60π) ² .
In addition, as the input impedance of the electric dipole antenna 27 becomes shorter than λo / 2, the negative reactance component increases rapidly, but the resistance component changes slowly, and the negative reactance component is reduced by the matching element. The input impedance in the case of canceling and resonating is in the range of approximately 70Ω to 50Ω.
Therefore, the input impedance at the opening 17 of the resonant waveguide antenna having the same waveguide width 25 as the dipole antenna length 25a is obtained from the equation of Babinet:
Zm = (60π) ² / Zj = (60π) ² / (70-50) = 508-710Ω
Become close.
The position of the RF connector terminal 18 (feed point) of the waveguide antenna will be described. When the waveguide width W 25 and the waveguide length L 29 are ¼ of the guide wavelength λg at the resonance frequency and the distance y′-28 from the opening 17 to the RF connector 18 is changed, the input impedance is changed. Is 0 [(y′−28 = λg / 4): short circuit part 11] <input impedance <
Zm [y′−28 = 0: impedance at the open end 17]
The pure resistance value in the range of That is, it is between 0Ω and (500 to 700) Ω. Therefore, by selecting an appropriate y′-28, the tuner input impedance can be matched to 75Ω.

  That is, the input impedance of the antenna in the RF connector 18 changes depending on the distance y'-28 shown in FIG. Further, when the DC voltage applied to the tuning element 18a is changed, the resonance frequency of the antenna is changed. When the resonance frequency is changed, the antenna input impedance viewed from the RF connector 18 at each resonance frequency is also changed. Therefore, the distance y′−28 is 75Ω, in which the input impedance of the antenna is the input impedance of the tuner when a direct current voltage is applied to the tuning element 18a to resonate the antenna close to 590 MHz at the center of the reception frequency band 470 MHz to 710 MHz. It is desirable to determine so that

  By connecting an RF cable (not shown) to the RF connector 18 as described above, it is possible to receive a TV broadcast radio wave and input it to a TV tuner in the receiver, and it can be used in the same manner as a normal TV indoor antenna. It becomes possible.

  Here, reference numeral 18 a in FIG. 2B denotes a tuning element that tunes the resonance frequency of the waveguide antenna to the frequency of the reception channel, and a DC voltage for tuning is given through the RF connector 18. In other words, a DC voltage is applied to the electronic tuning element 18a to change the reactance amount, and the resonance frequency of the waveguide antenna is tuned to the frequency of the reception channel. The DC voltage applied to the tuning element 18a is the RF connector 18. Given through the core wire.

  That is, as shown in FIG. 2 (b), the anode side of the tuning element 18a is connected to the inner wall of the metal waveguide 10, and the cathode side of the tuning element 18a is connected to the core wire of the RF connector 18. Is applied between the anode and cathode of the tuning element 18a by applying a DC voltage between the external metal of the RF connector and the RF connector.

The sound reproduction action of the waveguide antenna 10 of the present invention will be described with reference to FIGS. 3 (a) and 3 (b).
FIG. 3 (a) is a perspective view of the waveguide antenna of the present invention, and FIG. 3 (b) is a copy view seen from directly above. An audio signal generated from an audio player (speaker or the like) 12 attached to the short-circuited end 11 passes through the sound wave passage hole 14 to become a sound wave 32 shown in FIG. 3B, toward the open end of the waveguide. proceed.

  Here, the sound wave can pass through the hole formed in the short-circuited end 11, but the size of the hole is the wavelength of the reception frequency with respect to the current flowing in the waveguide wall and excited by the received radio wave. Can be ignored, there is no change in the action of shorting the electric field.

  Taking digital terrestrial broadcasting as an example, the band is from 470 MHz to 710 MHz, the wavelength is about 60 cm to 40 cm, and if the hole diameter is set to 2 cm or less of 1/20 of 40 cm, the antenna characteristics of the waveguide antenna The metal waveguide antenna portion and the speaker portion can be shared. Moreover, the hole shape does not need to be circular, and may be an ellipse, a rectangle, or other shapes, and the hole size only needs to be 2 cm or less. If the size of the hole is made too small, the sound is bulky and adversely affects the acoustic characteristics. Therefore, it is preferable to set it to be larger than several mm although it depends on the number of holes. The hole provided in the metal waveguide has no effect on the antenna characteristics if it is sufficiently small with respect to the wavelength at the maximum frequency of the radio wave, so it is determined in relation to the acoustic characteristics such as the size, shape and number of holes. To do.

  The sound wave traveling toward the open end travels while adjusting the sound along the acoustic adjustment mechanism 13 formed of a dielectric plate, and proceeds to the open end. Since the acoustic adjustment mechanism 13 is a dielectric plate, sound waves cannot pass through it, but the resonance electric field in the waveguide can pass through without problems. Then, the sound wave is reflected by the sound wave reflection / electric field passage mechanism 15 to change the traveling direction (the traveling direction is changed by about 90 degrees). Further, sound waves are emitted to the front surface of the waveguide shown in FIG.

  Here again, as described above, the sound wave is reflected because it cannot pass through the dielectric plate of the sound wave reflection / electric field passing mechanism 15, but the electric field can pass through without any problem, and the sound wave can be transmitted through the hole 16 formed in the waveguide wall. Can pass through, but the current excited by the received radio wave flowing through the waveguide wall is not obstructed, so that there is no change in the resonance characteristics of the waveguide. That is, the operation as a waveguide antenna is performed without any problem. According to the first embodiment, the waveguide antenna of the present invention can be used in a television receiver in combination with an audio reproducing device (speaker unit), and can be used without greatly detracting from the characteristics of a thin television. The waveguide antenna is operated as an acoustic adjustment tube and can be used like a television receiver dome / speaker, and can be easily arranged in a space in the receiver.

  The sound wave reflection plate 15 may be provided in the middle of the opening end surface 17 from the short-circuit end surface 14 not only from the position of the opening end 17 but also from the acoustic characteristics. Further, even in a thin digital broadcast receiver, depending on the thickness, if a metal waveguide is arranged in the thickness direction, the sound wave reflection plate 15 is unnecessary, and sound waves from the sound reproducing device are directly emitted from the opening end 17. Will be emitted.

  When a sound wave, which is an air dense wave, hits the wall surface, it is reflected back at a reflection angle equal to the incident angle. The harder the wall, the better the sound waves are reflected. Therefore, a resin dielectric having a high hardness and a low dielectric constant, such as polycarbonate, is suitable for the sound wave reflection plate 15 that reflects sound waves and allows electric fields to pass through. When designing to emit sound waves to the front of the receiver, The installation angle of the sound wave reflection plate 15 is preferably 45 degrees.

  The acoustic adjustment plate 13 as a sound quality adjustment mechanism constitutes an acoustic horn in the waveguide. An acoustic horn is an acoustic tube whose cross section gradually changes. Typical examples include a parabolic horn, a conical, an exponential horn, and a hyperbolic horn. In this embodiment, a conical horn whose cross section changes linearly. An example is shown.

  When a sound wave, which is a dense wave of air, hits an obstacle, a diffraction phenomenon occurs that wraps around the shadow. At the small hole, the sound wave that has passed through the hole supplies sound energy to the rear side of the small hole as a sound source of the area of the hole. Therefore, the sound wave can easily pass through the small hole provided in the waveguide wall which is a mechanism for reflecting the electric field and allowing the sound wave to pass therethrough, and further, the sound source can be operated at the position of the small hole.

  Next, a digital broadcast receiver according to the second embodiment of the present invention will be described.

  FIG. 4 shows the configuration of a digital broadcast receiver that is a flat-screen television 40. The metal waveguide portion sharing the functions of the metal waveguide antenna 10 and the speaker 12 of the receiver is connected to both ends of the receiver casing. Have in part. And it connects to the RF control part 41 with the RF cable from RF connector 18 installed in the electric power feeding terminal of the tuning element 18a of the metal waveguide antenna 10 arrange | positioned at the both ends of a broadcast receiver.

  Among the antenna characteristics, the directivity is omnidirectional in the horizontal plane as shown in FIGS. 2 (a) and 2 (b). The input characteristics are the same as the input matching characteristics of a parallel LC resonant circuit, which is a general antenna equivalent circuit model, and a circuit in which a radiation resistor Ra is connected in parallel, and the reflected signal amplitude at the input terminal is dip at the resonant frequency. Input characteristics. In digital television broadcasting using horizontally polarized waves, the metal waveguide antenna of the present invention can be disposed at both end portions of a thin receiver, and can be suitably used for a thin television broadcast receiver. Can do.

  In FIG. 4, television broadcast radio waves received by the waveguide antennas at both ends of the housing are input from the respective RF connectors 18 to the RF control unit 41 as received RF signals through cables or the like. A configuration in which a diversity antenna is configured using the RF signals input from the waveguide antennas at both ends to the RF control unit 41, and the RF signal is synthesized, for example, to obtain a good RF signal as a television reception signal. In addition, stable indoor reception is possible by inputting to a normal TV tuner.

  That is, by using the RF signals input from the waveguide antennas at both ends to the RF control unit 41, control of space diversity, phase synthesis diversity, etc. is performed, and a good RF signal is configured for television reception. Input to the tuner enables stable indoor reception.

  In the case of space diversity, control is performed by using a switch to select one of the received signals of the waveguide antennas at both ends with the switch. In phase synthesis diversity, one of the received signals of the waveguide antennas at both ends is received. A control is performed to add a phase delay to the signal and then add the amplitude to the other received signal. By using the broadcast receiver of the present invention, a digital television broadcast can be efficiently received even in a thin receiver.

  In addition, with the broadcast receiver of the present invention, it is possible to enjoy watching TV programs happily without worrying about the wiring of an RF cable, etc., even if it is carried anywhere in the room. It goes without saying that the waveguide antenna of the present application can be built in a receiver speaker with the same configuration in a receiver having a depth such as a conventional CRT television as well as a thin television receiver.

  The present invention does not require RF cable connection from outdoor or indoor antennas or RF cable rewiring from peripheral devices (for example, VCR, DVD / HDD recorder, etc.), and can be freely carried and arranged indoors for receiving digital broadcasts. This is useful for realizing a thin receiver at a low cost.

The figure which shows the broadcast receiving antenna in Embodiment 1 of this invention. The figure explaining the operation principle of the broadcast receiving antenna of the metal waveguide structure in Embodiment 1 of this invention The figure explaining the audio | voice reproduction machine comprised using the metal waveguide of the broadcast receiving antenna in Embodiment 1 of this invention The figure which shows the broadcast receiver in Embodiment 2 of this invention.

Explanation of symbols

10 Digital Broadcasting Reception Waveguide Antenna 11 Metal Waveguide Short-Circuit 12 Television Receiver Sound Reproducer (Speaker Sounder)
13 Acoustic adjustment mechanism (dielectric plate)
14 Sound wave passing and electric field short circuit mechanism (hole, slit, etc.)
15 Sound wave reflection and electric field passage mechanism (dielectric plate)
16 Sound wave passing and electric field short circuit mechanism (hole, slit, etc.) on one side
17 Open end of metal waveguide (antenna opening)
18 RF connector (feeding point)
21 Magnetic current H
22 Electric field E
24 Direction of radio wave reception 25 Waveguide width W
26 Waveguide thickness T
27 Waveguide antenna equivalent dipole antenna 28 Distance y ′ from waveguide end to feed point
29 Waveguide length L
31 Sound wave radiation direction 32 Sound wave 40 Thin television receiver 41 Reception RF signal control unit

Claims (8)

A magnetic current induction type digital broadcast receiving antenna,
A metal waveguide having a rectangular opening;
An audio player disposed on a short-circuited end surface of the metal waveguide facing the opening surface;
An acoustic adjustment mechanism comprising a pair of dielectric plates that form a horn that expands from the sound wave regenerator toward the opening surface in combination with the side wall of the waveguide to form a sound wave path in the waveguide;
A sound wave reflecting plate that opposes the short-circuit end face of the waveguide and reflects sound waves from the sound reproducer, and
The waveguide side wall has a plurality of sound wave passage holes through which sound waves from the sound wave reflecting plate pass.
A digital broadcast receiving antenna, wherein a sound wave radiated from the sound reproducing device is reflected by the sound wave reflection plate, and the reflected sound wave is propagated through the sound wave passage hole. The digital broadcast receiving antenna according to claim 1, wherein the short-circuit surface of the waveguide has a sound wave passage hole through which a sound wave radiated from the sound reproducer passes. A DC voltage applied to an electronic tuning element disposed in the waveguide for adjusting a resonance frequency of the waveguide is supplied via an RF connector for extracting the waveguide antenna output. Item 2. The digital broadcast receiving antenna according to Item 1. 2. The digital broadcast receiving antenna according to claim 1, wherein the size of the sound wave passage hole formed in the side wall of the waveguide is approximately 1/20 or less of the wavelength of the operating frequency. The sound wave reflecting plate is inclined with respect to the opening surface inside the waveguide in order to reflect the sound wave traveling from the sound reproducer to the opening surface and propagate the sound wave in a desired angle direction. 3. The digital broadcast receiving antenna according to claim 2, wherein the digital broadcast receiving antenna is closed. A magnetic current induction type digital broadcast receiving antenna,
A metal waveguide having a rectangular opening;
An audio player disposed on a short-circuited end surface of the metal waveguide facing the opening surface;
An acoustic adjustment mechanism comprising a pair of dielectric plates that form a horn that expands from the sound wave regenerator toward the opening surface in combination with the side wall of the waveguide to form a sound wave path in the waveguide;
With
The digital broadcast receiving antenna according to claim 1, wherein a short-circuit surface of the waveguide has a sound wave passage hole through which a sound wave radiated from the sound reproducer passes. A digital broadcast receiver for receiving a digital television broadcast, wherein the digital broadcast receiver according to claim 2 is provided at both end portions of the receiver. 8. The digital broadcast receiver according to claim 7, wherein diversity reception is performed using broadcast receiving antennas disposed at both side ends of the digital broadcast receiver.

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