JP2010057065A - Broadcast wave receiving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To receive a desired signal, in simple apparatus configuration, without greatly modifying the apparatus configuration, even if an electric field strength of a broadcast wave is varied. <P>SOLUTION: A broadcast wave receiving apparatus 10 includes: a first antenna 21 for receiving a broadcast signal; an amplifier 22 for amplifying the received broadcast signal; a tuner 24 for receiving input of the signal amplified by the amplifier 22; a housing section 11 having the first antenna 21, the amplifier 22 and the tuner 24 installed therein; and an outside antenna terminal 26 capable of being equipped with a second antenna 25. The broadcast signal received by the second antenna 25 is input to the amplifier 22 when the outside antenna terminal 26 is equipped with the second antenna 25. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a broadcast wave receiving apparatus that receives broadcast signals such as television broadcasts.

  In general, in a place where the electric field strength of a broadcast wave is strong, a terrestrial broadcast signal is often received using an indoor antenna that can be easily installed. FIG. 6 is a schematic diagram of a receiving apparatus that receives a terrestrial broadcast signal using an indoor antenna. The receiving apparatus 1 includes an antenna apparatus 2 with an amplifier (LNA: Low Noise Amplifier) 22 installed indoors, and a television tuner that is connected to the antenna apparatus 2 via a cable 5 and includes an LNA 301 and a tracking filter 302. (STB) 3 and a display device 4 connected to the television tuner 3. Drive voltages are supplied to the antenna device 2 and the television tuner 3 from a booster power source 6 and a tuner power source 7, respectively. Among such receiving apparatuses, there is an apparatus in which an antenna device and a television tuner are accommodated inside a metal casing to further simplify the configuration (Patent Document 1).

On the other hand, in places where the electric field strength of broadcast waves is weak, an outdoor antenna is often installed instead of the indoor antenna to receive terrestrial broadcast signals. FIG. 7 is a schematic diagram of a receiving device that receives a terrestrial broadcast signal using an outdoor antenna. In this receiving device 1, an antenna device 2a with an amplifier 22 is installed outdoors, and a television tuner 3 is connected to the antenna device 2a via a cable 5a, and a driving voltage is supplied from a booster power source 6. .
JP 2006-345238 A

  However, in the conventional receiving device, the installation location of the antenna devices 2 and 2a differs between a place where the electric field strength of the broadcast wave is strong and a weak location. Therefore, when the field strength changes, the installation location of the antenna devices 2 and 2a Accordingly, it is necessary to change the connection of the cable serving as the signal path, the power supply line 8 for supplying the driving voltage, and the like. In this case, a configuration in which the antenna devices 2 and 2a are provided both outdoors and indoors is conceivable. However, since the number of cables and power supply lines 8 is required for the number of antennas, the number of parts increases and the device configuration becomes complicated. There's a problem.

  The present invention has been made in view of such a point, and even when the electric field intensity of a broadcast wave changes, a broadcast that can receive a desired broadcast signal with a simple device configuration without significantly changing the device configuration. An object is to provide a wave receiver.

  The broadcast wave receiving apparatus of the present invention includes a first antenna for receiving a broadcast signal, an amplifier for amplifying the received broadcast signal, a tuner to which the signal amplified by the amplifier is input, the first antenna, A case in which the amplifier and the tuner are installed, and an external antenna terminal to which a second antenna for external installation can be attached, and the second antenna is attached to the external antenna terminal A broadcast signal received by the second antenna is input to the amplifier.

  According to this configuration, the first antenna, the amplifier, and the tuner are installed in the storage unit, and the external antenna terminal to which the second antenna for external installation can be attached is provided. It is possible to receive a desired broadcast signal with a simple device configuration without having to change the device configuration greatly, even in places where the intensity is strong or weak. In addition, the number of parts such as an LNA provided in the antenna and the tuner and a cable connecting the antenna and the tuner can be reduced as compared with the conventional receiver.

  In the broadcast wave receiving apparatus, when the broadcast signal is received by the second antenna, the first antenna is controlled so that an unnecessary frequency signal in the tuner does not flow into the tuner. Is preferred.

  According to this configuration, when a broadcast signal is received by the second antenna, the first antenna is controlled so that unnecessary frequency signals do not flow into the tuner. Broadcast signals can be received reliably.

  In the broadcast wave receiving apparatus according to the present invention, when a broadcast signal is received by the first antenna, the first antenna is tuned to a frequency of the received signal and broadcast by the second antenna. When receiving a signal, the first antenna is preferably tuned to the unwanted signal frequency.

  According to this configuration, when a broadcast signal is received by the first antenna, it is tuned to the frequency of the signal received by the first antenna, so that a broadcast signal in a desired frequency band can be received. When the broadcast signal is received by the second antenna, the first antenna is tuned to the signal frequency of the interference signal of the second antenna, so that the broadcast signal of the desired frequency band is transmitted via the second antenna. Can be received.

  In the broadcast wave receiving apparatus according to the present invention, it is preferable that the unnecessary signal frequency is an image frequency with respect to a frequency of a received signal. In this case, since an image frequency that is an interference frequency of the received signal is an unnecessary signal frequency, a desired broadcast signal can be reliably received.

  According to the present invention, in the broadcast wave receiving apparatus, the first antenna includes a tuning circuit including a variable capacitance element and an inductor element. In this case, since the first antenna having a tuning circuit functions as a tracking filter, it is not necessary to separately provide a tracking filter in the tuner as in the conventional receiving apparatus, and the number of components can be reduced.

  In the broadcast wave receiving apparatus according to the present invention, it is preferable that the second antenna is disconnected from the amplifier when the first antenna receives a broadcast signal.

  According to this configuration, when the electric field intensity of the broadcast wave is strong, the second antenna is disconnected from the amplifier and received by the first antenna. When the electric field intensity is weak, the second antenna is amplified. And can be received by the second antenna.

  According to the present invention, a desired broadcast signal can be received with a simple device configuration without greatly changing the device configuration even when the electric field strength of the broadcast wave changes.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The broadcast wave receiving apparatus according to the present embodiment is a broadcast wave receiving apparatus having an antenna installed indoors, and is used, for example, as a television signal receiving apparatus that receives a television signal for terrestrial broadcasting. It is. Hereinafter, a television signal receiving apparatus will be described as an example.

  1 and 2 are schematic diagrams schematically showing a television signal receiving apparatus (hereinafter referred to as “receiving apparatus”) according to an embodiment of the present invention. FIG. 1 shows the configuration of the receiving device when the electric field strength of the broadcast wave is weak, and FIG. 2 shows the configuration of the receiving device when the electric field strength of the broadcast wave is strong. As shown in FIGS. 1 and 2, the receiving device 10 includes a set top box (STB) 11, a power supply device 12 and a display device 13 connected to the STB 11, and these are installed indoors. ing.

  The STB (storage unit) 11 is configured by a single casing, and an indoor antenna (first antenna) 21 that functions as an indoor antenna, an LNA 22 connected to the antenna 21, and a cable 23 are provided inside the casing. And a television tuner 24 connected to the LNA 22 via The STB 11 is provided with an input terminal 26 as an external antenna terminal to which an outdoor antenna (second antenna) 25 installed outdoors can be attached. A signal path L1 from the input terminal 26 to which the outdoor antenna 25 is attached is connected to an intermediate point P between the antenna 21 and the LNA 22. Further, the STB 11 is provided with a power supply terminal 27, and the power supply device 12 is connected via a power cable 28. The power supply voltage from the power supply device 12 is supplied to the LNA 22 and the television tuner 24 via the power supply line L2.

  The antenna 21 is constituted by a tunable antenna whose tuning frequency is variable, for example, and receives a television signal and outputs it to the LNA 22. The LNA 22 amplifies the television signal output from the antenna 21 to a predetermined level, and outputs the amplified television signal to the television tuner 24. Here, when a tunable antenna is used as an indoor antenna, gain can be improved as compared with other antennas such as a passive antenna of the same size, which is preferable in terms of downsizing the STB 11.

  The antenna 21 has a tuning circuit including a variable capacitance element and an inductor element, and functions as a tracking filter that removes signals outside a desired frequency band. This eliminates the need for a tracking filter in the tuner as in the conventional receiving apparatus, and reduces the number of components.

  FIG. 3 is a circuit configuration diagram of a general tunable antenna 21. The tunable antenna 21 shown in FIG. 1 includes an antenna element 221 and a matching (tuning) circuit 222. The matching circuit 222 includes an LC series resonance circuit including varactor diodes (variable capacitance elements) 223 and 224 and a coil (inductor element) 225. A tuning voltage (antenna band control signal) for controlling the resonance frequency is applied to the anodes of the varactor diodes 223 and 224 from a television tuner 24 described later. Further, a coil 226 for matching with the television tuner 24 at the subsequent stage is connected in parallel to the output terminal of the matching circuit 222. Note that both ends of the matching circuit 222 are connected to the antenna element 221 and the LNA 22 via DC cut capacitors 227 and 228, respectively.

  The television tuner 24 mainly includes a mixer 31, a local oscillator 32, and a demodulator 33. The mixer 31 mixes the amplified signal output from the LNA 22 with the local oscillation signal generated by the local oscillator 32, converts it to a baseband frequency signal, and outputs the baseband frequency signal to the demodulation unit 33. The demodulator 33 demodulates the baseband frequency signal output from the mixer 31 and outputs the demodulated video / audio signal to the display device 13.

  The television tuner 24 can send an antenna band control signal S to the indoor antenna 21 to control the tuning frequency of the antenna 21. In particular, when the television tuner 24 receives a broadcast signal with the outdoor antenna 25, the television antenna 24 controls the indoor antenna 21 to function as a tracking filter so that unnecessary frequency signals in the television tuner 24 do not flow into the television tuner 24. . For example, when the indoor antenna 21 is used, the antenna 21 is tuned to the frequency of the received signal, while when the outdoor antenna 25 is used, the antenna 21 is tuned to the image frequency with respect to the frequency of the received signal. An antenna band control signal S is transmitted. As a result, when the broadcast signal is received by the outdoor antenna 25, the antenna 21 is tuned to the image frequency, so that the image frequency signal that becomes a disturbance signal flows into the antenna 21 side and is attenuated, and the television tuner 24 side. Inflow to the is prevented.

Next, the operation of the signal receiving apparatus 10 according to the present embodiment will be described.
In a place where the electric field intensity of the broadcast wave is weak, an outdoor antenna is used to improve the signal reception quality level, so the antenna 25 is connected to the input terminal 26 as shown in FIG. The television signal received by the antenna 25 is output to the LNA 22 via the signal path L1, amplified to a predetermined level by the LNA 22, and then output to the television tuner 24. At this time, since the antenna band control signal S for setting the tuning frequency to the image frequency is input to the indoor antenna 21 from the television tuner 24, the frequency is controlled so that the impedance of the antenna 21 is lowered. It has become. Therefore, the image frequency signal included in the reception signal of the antenna 25 is output to the antenna 21 via the signal path L1, and only a desired signal is output to the LNA 22. On the other hand, since the signal reception quality level can be maintained without using an outdoor antenna in a place where the electric field intensity of the broadcast wave is strong, the outdoor antenna 25 is disconnected from the LNA 22 as shown in FIG. The television signal received by the indoor antenna 21 is output to the LNA 22, amplified to a predetermined level, and then output to the television tuner 24. Here, as a method for disconnecting the outdoor antenna 25 and the LNA 22, in addition to removing the outdoor antenna 25 from the input terminal 26, a switch unit for switching connection / disconnection of the antenna 25 at the intermediate point P may be provided.

  4 and 5 are characteristic diagrams showing signal passing characteristics of the television tuner 24 when received by the outdoor antenna 25. FIG. FIG. 4 shows the pass characteristic when the reception channel frequency is 473 MHz, and FIG. 5 shows the pass characteristic when the reception channel frequency is 580 MHz. In both figures, solid lines (W1, W3) indicate the transmission characteristics of the television tuner 24, and dotted lines (W2, W4) indicate the reflection characteristics as viewed from the television tuner 24 side. As can be seen from W1 shown in FIG. 4, the loss is minimized at the reception channel frequency of 473 MHz, a trap is formed at the image frequency, and the image frequency is removed. Similarly, W3 shown in FIG. 5 has a minimum loss at the reception channel frequency of 580 MHz, a trap is formed at the image frequency, and the image frequency is removed.

  As described above, according to the present embodiment, the indoor antenna 21, the LNA 22 and the television tuner 24 are installed in the STB (storage section) 11, and the input terminal 26 to which the outdoor antenna 25 for external installation can be attached. Since it is provided, it is possible to receive a desired broadcast signal with a simple device configuration without having to significantly change the device configuration in a place where the electric field intensity of the broadcast wave is strong or weak. In particular, when the broadcast signal is received by the outdoor antenna 25 when the electric field intensity of the broadcast wave is weak, the antenna 21 functions as a tracking filter by tuning to the image frequency of the frequency received by the antenna 21. The input of the image frequency signal to the television tuner 24 side can be cut, and only a desired broadcast signal can be reliably received. Further, as compared with the conventional receiving apparatus, the number of components such as the LNA 22 provided in the antennas 21 and 25 and the television tuner 24 and the cable 23 connecting the antennas 21 and 25 and the television tuner 24 can be reduced. .

  The present invention is not limited to the above-described embodiment, and can be implemented with various modifications. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited thereto, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  The present invention is applicable to a broadcast wave receiving apparatus that receives a broadcast signal such as a television broadcast.

It is a schematic diagram which shows the television signal receiver which concerns on embodiment of this invention. It is a schematic diagram which shows the television signal receiver which concerns on embodiment of this invention. It is a circuit block diagram of a general tunable antenna It is a characteristic view which shows the signal passage characteristic in a television tuner. It is a characteristic view which shows the signal passage characteristic in a television tuner. It is a schematic diagram which shows the conventional television signal receiver. It is a schematic diagram which shows the conventional television signal receiver.

Explanation of symbols

10 Television signal receiver 11 Set top box (storage part)
12 power supply device 13 display device 21 indoor antenna (first antenna)
22 LNA
23 Cable (TV cable)
24 Television tuner 25 Outdoor antenna (second antenna)
26 Input terminal 27 Power terminal 28 Cable (power cable)
31 Mixer 32 Local oscillator 33 Demodulator L1 Signal path L2 Power supply line P Intermediate point

Claims (6)

  A first antenna for receiving a broadcast signal, an amplifier for amplifying the received broadcast signal, a tuner to which a signal amplified by the amplifier is input, and the first antenna, the amplifier and the tuner are installed. A storage unit, and an external antenna terminal to which a second antenna for external installation can be attached. When the second antenna is attached to the external antenna terminal, the second antenna receives the second antenna. A broadcast wave receiving apparatus, wherein a broadcast signal is input to the amplifier.   2. The broadcast wave reception according to claim 1, wherein when the broadcast signal is received by the second antenna, the first antenna is controlled so that an unnecessary frequency signal in the tuner does not flow into the tuner. apparatus. When receiving a broadcast signal with the first antenna, the first antenna is tuned to the frequency of the received signal;
3. The broadcast wave receiving apparatus according to claim 2, wherein when the broadcast signal is received by the second antenna, the first antenna is tuned to the unnecessary signal frequency.   4. The broadcast wave receiving apparatus according to claim 2, wherein the unnecessary signal frequency is an image frequency with respect to a frequency of a received signal.   5. The broadcast wave receiving apparatus according to claim 1, wherein the first antenna includes a tuning circuit including a variable capacitance element and an inductor element.   6. The broadcast wave receiving apparatus according to claim 1, wherein when the broadcast signal is received by the first antenna, the second antenna is disconnected from the amplifier. .

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