JP2004007130A - Ground wave broadcast receiving system and ground wave broadcast receiving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable an analog tuner and a digital tuner to be supplied with signals having suitable levels in accordance with the difference of receiving sensitivity. <P>SOLUTION: A signal from an antenna is divided by a branching unit 13 and output from an output terminal and a branched output terminal. The signal obtained from the output terminal 13b is supplied to the analog tuner 16, and the signal from the branched output terminal 13c is supplied to the digital tuner 17. When digital broadcast is received, the grade of the received signal at the digital tuner 17 is discriminated by a discriminating means 30. When the grade goes down beyond a predetermined threshold, the signal from the output terminal 13b of the branching unit 13 is switched to be supplied to the digital tuner 17. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a terrestrial broadcast receiving apparatus and a receiving method for appropriately receiving a broadcast in a situation where analog and digital broadcasts are expected to be mixed when terrestrial digital broadcast is started in the near future.
[0002]
[Prior art]
Digitalization of terrestrial television broadcasting has been started in some regions since 2003, and plans for digital broadcasting to replace analog broadcasting in all regions in 2010 are being promoted.
Therefore, it is conceivable that analog broadcasting and digital broadcasting will be simultaneously performed in the same service area until 2010, and the viewer will purchase a receiver compatible with digital broadcasting during this period.
In the case of broadcasting the same program simultaneously in digital broadcasting and analog broadcasting, it is only necessary to acquire a receiver that supports only digital broadcasting, but not all channels are digitized at the same timing. Cannot receive a channel whose digitization is delayed.
[0003]
Therefore, during a period in which analog broadcasting is also implemented, a device capable of receiving both analog broadcasting and digital broadcasting can be said to be a product suitable for practical use.
A receiver equipped with both an analog tuner and a digital tuner may be configured to supply a signal from a common antenna input terminal to both tuners via a distributor.
With this configuration, analog broadcasting and digital broadcasting can be received by a common antenna.However, digital tuners generally have higher reception sensitivity than analog tuners. Is more efficient if it is distributed to both tuners.
[0004]
Conventionally, proposals have been made to enable reception of both analog broadcasting and digital broadcasting (for example, Japanese Patent Application Laid-Open No. 2001-230689), but the reception efficiency is improved by focusing on the difference in reception sensitivity between the analog tuner and the digital tuner. No proposal has been made focusing on this point.
[0005]
[Problems to be solved by the invention]
As described above, in the related art, in a receiver capable of receiving both an analog broadcast and a digital broadcast, there is no device that efficiently receives both the broadcasts.
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made in consideration of the receiving sensitivity of each tuner, and has a terrestrial broadcast receiving apparatus and a terrestrial broadcast capable of efficiently receiving both broadcasts. It is intended to provide a receiving method.
[0006]
[Means for Solving the Problems]
The terrestrial broadcast receiving apparatus according to the present invention includes an input terminal to which a signal from an antenna is supplied, and a signal supplied to the input terminal, which is led to a first output terminal with a first insertion loss, and A signal distribution means for leading to a second output terminal with a second insertion loss greater than the insertion loss of 1 and receiving a terrestrial analog broadcast channel with a signal supplied to the first output terminal as an input; A first tuner that receives a signal supplied to the second output terminal, receives a terrestrial digital broadcast channel, and outputs a received signal, and an output of the first tuner. And output means for selectively selecting an output of the second tuner to derive a reception signal of the selected tuner.
[0007]
According to the present invention, appropriate reception can be performed by connecting a digital tuner having high reception sensitivity to an output terminal having a large insertion loss and connecting an analog tuner to an output terminal having a small insertion loss.
The terrestrial broadcast receiving apparatus according to the present invention further includes an input terminal to which a signal from an antenna is supplied, and a signal supplied to the input terminal, which is led to an output terminal with a first insertion loss, and Branching means for leading to a branch output terminal with a second insertion loss larger than the first insertion loss; and a first means for receiving a terrestrial analog broadcast channel with a signal derived from the output terminal as input and outputting a received signal , A second tuner that receives a terrestrial digital broadcast channel by receiving a signal supplied to the branch output terminal, and outputs a received signal, a reception output of the first tuner, and a second tuner Switching means for selectively switching the reception output of the second tuner to output a reception signal of the selected tuner, and the second means in a state where the output of the second tuner is selected by the switching means. Based on the received signal outputted from the tuner, characterized in that a signal derived from the output terminal of the branching means and and control means for switching to the input of the second tuner.
[0008]
According to the present invention, a signal derived from an output terminal having a small insertion loss with respect to an output is supplied to an analog tuner, a signal derived from a branch output terminal having a large insertion loss is supplied to a digital tuner, and received by the digital tuner. If the reception state deteriorates while watching the signal, the signal can be switched to supply the signal from the output terminal of the branching means to the digital tuner, so that appropriate reception can be performed.
[0009]
Further, in the terrestrial broadcast receiving method of the present invention, a broadcast signal to which a signal from an antenna is supplied is led to a first output terminal with a first insertion loss, and a second signal having a second insertion loss larger than the first insertion loss is obtained. Deriving to a second output terminal with insertion loss, receiving a terrestrial analog broadcast channel of a signal supplied to the first output terminal with a first tuner, and outputting a received signal; Receiving a terrestrial digital broadcast channel from a signal supplied to a second output terminal with a second tuner and outputting a reception signal; and outputting the first output signal based on the reception signal of the second tuner. Setting the signal supplied to the terminal to be received by the second tuner.
[0010]
According to the present invention, the digital tuner is connected to the output terminal having a large insertion loss of the signal distribution means, and the analog tuner is connected to the output terminal having a small insertion loss. Since it is connected to the output terminal of the distribution means having a small insertion loss, appropriate reception can be performed.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing an embodiment of the terrestrial broadcast receiving apparatus according to the present invention.
The receiver 10 has an antenna terminal 12 for receiving a signal from an antenna 11, and receives a signal supplied to the antenna terminal 12 by a splitter 13.
The branching device 13 includes an input terminal 13a, an output terminal 13b, and a branch output terminal 13c connected to an antenna terminal. Assuming that the insertion loss of the splitter 13 is, for example, 10 dB as a whole, the insertion loss between the input terminal 13a and the output terminal 13b is, for example, 1 dB, and the insertion loss between the input terminal 13a and the branch output terminal 13c is, for example, 9 dB. .
[0012]
Such a branching device has been widely used in the past, and its specific circuit configuration is described in, for example, JP-A-56-115017.
The output terminal 13 b of the branching device 13 is connected to the first input terminal 14 a of the first changeover switch 14 and to the first input terminal 15 a of the second changeover switch 15.
The branch output terminal 13c of the branching device 13 is connected to the second input terminal 14b of the first changeover switch 14 and to the second input terminal 15b of the second changeover switch 15.
The output terminal 14c of the first changeover switch 14 is connected to the input terminal of the analog tuner 16, and the output terminal 15c of the second changeover switch 15 is connected to the input terminal of the digital tuner 17.
The signal received by the analog tuner 16 is converted into a baseband video signal and an audio signal by a demodulation / signal processing unit 18 and appropriately processed, and the audio signal is converted to a first input of a third switch 19. The video signal is supplied to the terminal 19a, and the video signal is supplied to the first input terminal 20a of the fourth changeover switch 20.
[0013]
The signal received by the digital tuner 17 is subjected to OFDM (Orthogonal Frequency Division Multiplexing) demodulation and error correction by the decoder 21, and is decoded and decoded by MPEG (Moving Picture Experts Group). The video signal is subjected to processing such as graphic superposition as required by the graphic processing unit 22, further converted into an analog signal, and supplied to the second input terminal 20 b of the fourth switch 20. Further, the decoder 21 also performs MPEG decoding on the audio signal, converts the decoded audio signal into an analog signal, and supplies the analog signal to the second input terminal 19 b of the third switch 19.
[0014]
The output terminal 19c of the third changeover switch is connected to the audio output unit 23, where the audio signal is amplified and supplied to the speaker 24 to be output as audio.
The output terminal 20c of the fourth changeover switch is connected to the video output unit 25, and the supplied video signal is amplified and supplied to the display unit 26 composed of a cathode ray tube or the like for display.
Further, the receiver 10 is provided with an input unit 27 for the user to operate, and receives a remote control signal from a remote control hand unit (not shown) to receive a control signal for controlling the operation and functions of the receiver 10. It is supplied to a control unit 28 composed of a microcomputer or the like. The input unit 27 may be composed of a plurality of switches provided on the front surface of the housing of the receiver 10.
[0015]
When a control signal related to channel selection is supplied from the input unit 27, the control unit 28 operates the channel selection unit 29 to switch the reception channel of the analog tuner 16 or the digital tuner 17.
Further, the control unit 28 outputs a control signal for switching the third and fourth changeover switches 19 and 20 according to a received broadcast selection control signal supplied from the input unit 27 by the user. As a result, analog broadcasting or digital broadcasting is selectively received.
Further, the receiver 10 is provided with a determination unit 30 for determining the quality of the received signal from the received output of the digital tuner 17. The determination unit 30 determines the quality of the received signal from the BER (Bit Error Rate) or C / N (Carrier / Noise: carrier / noise ratio) of the output of the digital tuner 17, and when the values exceed a predetermined threshold value. In the case of deterioration, a signal for causing the first and second changeover switches to perform switching is output.
[0016]
The operation of the receiver 10 configured as described above will be described.
For example, in an initial state such as immediately after turning on the power of the receiver 10, the first changeover switch 14 selects the first input terminal 14a, and the second changeover switch 15 selects the second input terminal 15b. Is switched to
That is, the output terminal 13 b of the branch unit 13 is connected to the analog tuner 16, and the branch output terminal 13 c of the branch unit 13 is connected to the digital tuner 17.
In general, the digital tuner 17 has higher reception sensitivity than the analog tuner 16, so that the input signal level can be set smaller than that of the analog tuner 16.
That is, by connecting the digital tuner 17 to the branch output terminal 13 c of the branch unit 13 having a large insertion loss and connecting the analog tuner 16 to the output terminal 13 b of the branch unit 13 having a small insertion loss, the two tuners 16 and 17 are appropriately connected. Operating state.
[0017]
When receiving an analog broadcast, the user supplies a control signal from the input unit 27 to the tuning unit 29 via the control unit 28 to tune to a desired analog broadcast channel, and at the same time, selects a third channel via the control unit 28. And the fourth changeover switches 19 and 20 are switched so as to select the reception signal of the analog tuner 16.
[0018]
When receiving a digital broadcast, the user supplies a control signal from the input unit 27 to the tuning unit 29 via the control unit 28 to select a desired digital broadcast channel, and at the same time, selects a third digital broadcast channel via the control unit 28. And the fourth changeover switches 19 and 20 are switched so as to select the reception signal of the digital tuner 17.
[0019]
In the reception state of the digital broadcast, the signal state of the reception output of the digital tuner 17 is determined by the determination unit 30, and the quality of the signal is monitored. When the value of the BER or C / N of the reception output of the digital tuner 17 changes in a direction in which the BER or C / N exceeds a predetermined threshold value, the discriminator 30 switches the second changeover switch 15 to the first input terminal 15a, and The first switch 14 is switched to the second input terminal 14b.
[0020]
As a result, the digital tuner 17 is connected to the output terminal 13b of the splitter 13, and a large-level antenna output signal is supplied.
At this time, the analog tuner 16 is connected to the branch output terminal 13c of the branching unit 13 by switching the first switch 14 to the second input terminal 14b. However, since there is no analog broadcast reception state, no problem is caused by this switching.
[0021]
Next, when receiving an analog broadcast, the digital tuner 17 is set, for example, to a non-operating state by the control signal from the input unit 27 via the tuner 29, and the discriminating unit 30 discriminates the non-operating state. The first switch 14 is switched to select the first input terminal, and the second switch 15 is switched to select the second input terminal.
[0022]
As a result, the analog tuner 16 again receives the high-level signal supplied from the output terminal 13b of the splitter 13.
The first and second changeover switches 14 and 15 select the first input terminal 14a and the second input terminal 15b by the control unit 28 when the user switches the broadcast to be received from digital to analog. It is also possible to control so that
FIG. 2 is a flowchart for explaining the operation of the receiving apparatus shown in FIG.
Starting at step 2a, the setting is made such that the output terminal 13b of the splitter 13 is connected to the analog tuner 16 and the branch output 13c of the splitter 13 is connected to the digital tuner 17 at step 2b.
Next, it is determined in step 2c whether the received broadcast is an analog broadcast or a digital broadcast. If the received broadcast is an analog broadcast, the process returns to step 2b.
If digital broadcast reception is selected, the quality of the received signal of the digital tuner 17 is determined in step 2d. If the quality of the received signal is not lower than the predetermined threshold in step 2e, the process returns to step 2d. If the value falls below a predetermined threshold value, switching is performed so that the digital tuner 17 is connected to the non-branch output terminal 13b of the branching unit 13 in step 2f.
[0023]
Next, in step 2g, it is determined whether or not analog broadcast reception is selected. If analog broadcast reception is selected, the process returns to step 2b, where the analog tuner 16 is connected to the output terminal 13b of the branching device 13 again, and the branching is performed. The digital tuner 17 is connected to the branch output terminal 13 c of the device 13.
[0024]
In the embodiment described above, the digital tuner 17 is automatically connected to the output terminal 13b of the branching unit 13 based on the determination result of the determination unit 30 when viewing a digital broadcast. However, if the first and second changeover switches 14 and 15 can be switched, the usability is further improved.
[0025]
FIG. 3 is a block diagram showing an embodiment in which the user can manually switch the first and second changeover switches 14 and 15.
The difference from FIG. 1 is that the control unit 28 and the discriminating unit 30 are connected and a control signal is supplied to the discriminating unit 30. Other parts are the same as those in FIG. I do.
That is, when the user determines that the user wants to supply the signal from the output terminal 13 b of the branching device 13 to the digital tuner 17 while receiving the digital broadcast, the control signal is sent from the input unit 27 to the determination unit 30 via the control unit 28. And the first changeover switch 14 can be controlled to select the first input terminal 14a.
[0026]
According to this, the quality of the received signal does not decrease so as to exceed the threshold, but when the user determines that he / she wants to view in a good reception state, the input signal level of the digital tuner 17 is increased by the user's intention. , Can achieve the purpose.
Further, when receiving an analog broadcast, the first changeover switch 14 can be configured to be switched so that the first input terminal 14a and the analog tuner 16 are always connected.
During reception of the analog broadcast, the analog tuner 16 is always connected to the first input terminal 14a of the first changeover switch 14. Therefore, the path connecting the branch output terminal 13c of the branching unit 13 and the analog tuner 16 is Therefore, the second input terminal 14b of the first changeover switch 14 may not be connected to the branch output terminal 13c, but may be configured to exist only as a terminal.
[0027]
During reception of the analog broadcast, the digital tuner 17 may be in an operating state or a non-operating state. Similarly, during digital broadcast reception, the analog tuner 16 may be in an operating state or a non-operating state.
As described above, according to the present invention, it is possible to achieve a lean signal distribution that matches the characteristics of each tuner, and further, when the reception state of the digital tuner deteriorates, it is possible to overcome the problem. Thus, a good reception state can always be obtained.
[0028]
【The invention's effect】
As described above, according to the present invention, a signal from the antenna is supplied to the analog tuner through the output terminal of the branch unit, and the digital tuner with high reception sensitivity receives the signal from the antenna through the branch output terminal of the branch unit. And when the received signal quality of the tuner falls below a predetermined threshold during digital broadcast viewing, the signal from the output terminal of the splitter is set to be supplied to the tuner, so that there is no waste. And a good reception state can always be obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of a terrestrial broadcast receiving apparatus according to the present invention.
FIG. 2 is a flowchart for explaining the operation of the apparatus shown in FIG. 1;
FIG. 3 is a block diagram showing another embodiment of the terrestrial broadcast receiving apparatus according to the present invention.
[Explanation of symbols]
Reference Signs List 10 receiver 11 antenna 12 antenna input terminal 13a output terminal 13c branch output terminal 14 first changeover switch 15 second changeover switch 19 third changeover switch 20 fourth changeover switch

Claims (7)

An input terminal to which a signal from the antenna is supplied;
Signal distribution means for leading a signal supplied to the input terminal to a first output terminal with a first insertion loss and leading to a second output terminal with a second insertion loss larger than the first insertion loss. When,
A first tuner that receives a terrestrial analog broadcast channel with a signal supplied to the first output terminal as an input, and outputs a received signal;
A second tuner that receives a terrestrial digital broadcast channel using a signal supplied to the second output terminal as an input, and outputs a received signal;
Output means for selectively selecting an output of the first tuner and an output of the second tuner to derive a reception signal of the selected tuner;
A terrestrial broadcast receiver comprising: Further, in a state where the output of the second tuner is selected by the switching means, the signal derived from the first output terminal of the signal distribution means is converted to the second signal based on the reception signal of the second tuner. 2. The terrestrial broadcast receiving apparatus according to claim 1, further comprising control means for switching the input to a tuner. An input terminal to which a signal from the antenna is supplied;
Branching means for leading a signal supplied to the input terminal to an output terminal with a first insertion loss, and leading to a branch output terminal with a second insertion loss larger than the first insertion loss;
A first tuner that receives a terrestrial analog broadcast channel with a signal derived from the output terminal as an input, and outputs a received signal;
A second tuner that receives a terrestrial digital broadcast channel by using a signal supplied to the branch output terminal as an input, and outputs a received signal;
Switching means for selectively switching the reception output of the first tuner and the reception output of the second tuner to output a reception signal of the selected tuner;
In the state where the output of the second tuner is selected by the switching means, a signal derived from an output terminal of the branching means is input to the input of the second tuner based on a reception signal output from the second tuner. Control means for switching to
A terrestrial broadcast receiver comprising: The control unit switches a signal derived from an output terminal of the branching unit to be an input of the second tuner based on a bit error rate of a reception signal output from the second tuner. 4. The terrestrial broadcast receiving apparatus according to claim 3, wherein: The control means switches a signal derived from an output terminal of the branching means to be an input of the second tuner based on a carrier-to-noise ratio of a received signal output from the second tuner. 4. The terrestrial broadcast receiving apparatus according to claim 3, wherein: The control means can set whether to derive the output of the output terminal of the splitter to the first tuner or to the second tuner independently of the reception signal of the second tuner. The terrestrial broadcast receiver according to claim 3, wherein: Deriving a broadcast signal to which a signal from an antenna is supplied to a first output terminal with a first insertion loss and deriving the broadcast signal to a second output terminal with a second insertion loss larger than the first insertion loss When,
Receiving a terrestrial analog broadcast channel among the signals supplied to the first output terminal with a first tuner and outputting a received signal;
Receiving a terrestrial digital broadcast channel among the signals supplied to the second output terminal with a second tuner and outputting a received signal;
Setting a signal supplied to the first output terminal to be received by the second tuner based on a reception signal of the second tuner;
A terrestrial broadcast receiving method, comprising:

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