JPH11355751A - Digital broadcast receiving apparatus and control method thereof - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To detect a failed IC card and separate the IC card to limit the influence of the failure. SOLUTION: The digital broadcast receiving apparatus 1 is constituted by a receiving apparatus main body 3 and IC cards 5 and 7 which are detachable therefrom. The test signal multiplexing circuit 101 multiplexes a test input signal with a broadcast signal at a stage preceding the daisy chain connected IC cards. Signal processing circuit 10 in IC cards 5 and 7
Reference numerals 20, 1022 denote test output signals without performing any processing on the test input signal. Test signal detection circuit 102
The test output signal detected in step (1) is compared and determined by the determination circuit 106 with the correct answer value. If the test result is bad, the switches 1009 and 1 corresponding to the IC card determined to be faulty
010, 1011 and 1012 are switched to bypass the failed IC card.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcast receiving apparatus for receiving and viewing digital broadcasts such as a satellite broadcast and a cable television (hereinafter abbreviated as CATV) system and a test method thereof. The present invention relates to an improvement in an interface between a detachable unit such as an IC card for performing signal processing such as scrambling and a receiving apparatus main body.

[0002]

2. Description of the Related Art In recent years, a plurality of service providers have appeared in digital satellite broadcasting services, and it has been inconvenient to install a different receiving device for each provider. In order to solve this inconvenience, a common use of a receiving apparatus has been studied while supporting scrambling for each broadcasting station.

[0003] For example, there is DVB (Digital Video Broadcasting) as a digital broadcasting standard organization in Europe.
One of the standards is a common interface (Co
mmonInterface) standard (EN50221). This common interface standard is an interface standard between the receiving device main unit and the card unit. In particular, when watching pay broadcast, the scramble received by the receiving device main unit, that is, the encrypted broadcast signal is descrambled by the card unit, that is, the encryption is performed. This is a standard for signal transmission and reception between the receiving device body and the card unit for decoding.

Next, the operation of a digital broadcast receiving apparatus adopting the common interface standard will be described with reference to FIG. The digital broadcast receiving apparatus 1000 includes a receiving apparatus main body 1001 and an IC card 1002 detachable therefrom,
1003.

[0005] The digital broadcast receiving apparatus 1000 has a terminal 1
A broadcast signal such as a satellite broadcast or a CATV broadcast input to 004 is received and demodulated, and the received and demodulated broadcast signal is output to a television so that a user can view a broadcast program.

[0006] Generally, there is a pay broadcast, and a broadcast signal is scrambled, that is, encrypted, and transmitted from a broadcast station to a receiver. In the receiving device of the user who has made the viewing contract, the scrambled broadcast signal is descrambled, that is, encrypted and decrypted by an externally connected IC card, decoded, and viewed on a television. A frequency multiplexed and / or time division multiplexed digital broadcast signal is input to a terminal 1004, and a signal of a frequency corresponding to the program selected by the tuner / demodulation circuit 1006 is selected and demodulated.

In general, in digital broadcast transmission, program information is transmitted with an error correction code added thereto.
In step 7, the broadcast signal is corrected for transmission errors. This error correction circuit output signal stream is MPE
This is a format of the G-SYSTEM (ISO / IEC13818-1) standard, in which signals of a plurality of programs are time-division multiplexed. In some cases, a signal is input from a terminal 1005 from a signal generation device external to the reception device.
Use to select a signal.

This signal stream is transmitted to the
1, and is descrambled by a signal processing circuit (descrambler) 1020.
That is, the encryption is decrypted and input to the receiving device 1001 again. In the signal processing of the stream signal, only a necessary portion of the stream signal is performed, and nothing is performed for a portion that does not require the signal processing. For example, when a signal in which a plurality of programs are multiplexed is input to an IC card and descrambling of the selected program is performed, descrambling processing is performed only on the selected program portion of the input stream signal. And output it to the receiving device.

In this receiver, an example in which a plurality of IC cards can be connected to support a plurality of pay broadcasting systems is shown, but input / output signals between the IC cards are daisy-chain connected. That is, the signal output of the error correction circuit 1007 performs signal processing as necessary via the IC card 1002, returns to the switch 1010, performs signal processing again as necessary via the IC card 1003, and performs switch processing on the switch 1012. Return to In the example of FIG. 7, two descramblers are shown as functions of the IC card.
C cards may be connected in a daisy chain and IC
As an application of the card, for example, a text broadcast receiving function, an external output interface, or the like may be used.

Each IC card performs communication between a control circuit 1017 in the receiving device and control circuits 1021 and 1023 in the card, such as control of a signal processing circuit. The signal subjected to the signal processing is used to select a necessary signal from the program signals time-division multiplexed by the DEMUX circuit 1013. Further, the video / audio decoding circuit 1014 decodes the digital compression-coded video / audio signal, performs D / A conversion, system conversion, etc. in the video / audio output circuit 1015.
16 to the television.

The IC card is detachable from the main body of the receiving device, and the user inserts and removes various IC cards according to the purpose. When the IC card 1002 is removed, the receiving device main body 1001 detects that the IC card 1002 has been removed by the card detection circuit 1018, and controls the switch 1010 from the control circuit 1017 to switch to the signal side that bypasses the IC card 1002. . On the other hand, when the IC card is inserted, the card detection circuit 1
The control circuit 1017 controls the switch 1010 to switch to the output signal side of the IC card. Switch 1009
Is a switch for preventing a signal from being output to the outside of the receiving device when the card is removed, and is necessary for preventing a signal from being exposed to the outside when the IC card is removed.

As described above, in the conventional digital broadcast receiving apparatus, since the IC card 1003, the DEMUX circuit 1013, and the video / audio decoding circuit 1014 are connected after the IC card 1002,
When 002 breaks down, especially when the broadcast signal system cannot be propagated, the subsequent system malfunctions or becomes inoperable, greatly affecting the entire receiving system.

[0013]

As described above,
In a conventional digital broadcast receiving apparatus, one or more I
C cards are daisy-chain connected, and a DEMUX circuit, a video / audio decoding circuit, and the like are connected at the subsequent stage of these IC cards. If a certain IC card breaks down and the broadcast signal system cannot be propagated, The subsequent system malfunctions or becomes inoperable, and more than simply losing the function of the failed IC card, it has a great effect on the entire receiving system, such as receiving and receiving functions of channels that do not use the function of this IC card. There is a problem that occurs.

In view of the above problems, the present invention detects a failure by performing a test of a broadcast signal system for each IC card and detects a failure IC.
The purpose of the present invention is to separate the card from the system and prevent a great influence on the entire receiving system.

[0015]

In order to achieve the above object, the present invention provides a signal obtained by receiving and demodulating a digital broadcast in a first device, or a demodulated packet supplied from a signal supply device external to the first device. Output the broadcast signal of the format to one or more second devices connected in a daisy chain via the first device, perform signal processing of the input signal in the second device, and again perform the first A control method in a digital broadcast receiving apparatus for outputting a signal after signal processing in the first apparatus and multiplexing a test signal with a broadcast signal in a stage prior to the second apparatus; This is a control method in which the first device detects a test signal output from the second device, and disconnects the second device based on the detection result.

Further, according to the present invention, a signal obtained by receiving and demodulating a digital broadcast in the first device or a demodulated packet-format broadcast signal provided from a signal supply device external to the first device is transmitted to the first device by using the first device. Output to one or more separable second devices, perform signal processing of the input signal in the second device, and then output again to the first device, and perform signal processing in the first device. Connection means for daisy-chaining one or more of the second devices, and test signal multiplexing means for multiplexing a test signal with a broadcast signal at a stage preceding the second device Test signal detection means for detecting a test signal output from the second device in the first device; a signal bypassing the second device; and an output signal of the second device. One or more switch means for switching, and disconnection control means for controlling the switch means to disconnect the second device from the first device when the test signal cannot be detected by the test signal detection means, Is a digital broadcast receiving apparatus having a gist.

Further, the present invention provides a method for receiving a signal obtained by demodulating a digital broadcast in a first device or a demodulated packet-format broadcast signal provided from a signal supply device external to the first device. Output to one or more separable second devices, perform signal processing of the input signal in the second device, and then output again to the first device, and perform signal processing in the first device. Connection means for daisy-chaining one or more of the second devices, and test signal multiplexing means for multiplexing a test signal with a broadcast signal at a stage preceding the second device Test signal detection means for detecting the test signal output from the second device in the first device; a signal bypassing the second device; and an output of the second device. And one or more switch means for switching between the first device and the second device. The connection control device sequentially controls the one or more switch devices to sequentially connect the second device to the first device. A digital broadcast receiving apparatus, comprising: disconnection control means for controlling the switch means to disconnect the second device from the first device when the test signal cannot be detected.

Further, the present invention provides a method for receiving a demodulated digital broadcast signal in a first device or a demodulated packet-format broadcast signal provided from a signal supply device external to the first device, by combining the first device with the first device. Output to one or more separable second devices, perform signal processing on the input signal in the second device, output again to the first device, and perform signal processing in the first device. A connection means for daisy-chaining one or more second devices in a digital broadcast receiving device for decoding and outputting a signal; and a test input to a broadcast signal at an input of each of the second devices in the first device. Test signal multiplexing means for multiplexing a signal, and test signal detecting means for detecting a test signal multiplexed on the broadcast signal at an output of each of the second devices in the first device. One or more switch means for switching a signal bypassing the second device and an output signal of the second device; and controlling the switch means when the test signal detection means cannot detect the test signal, And a disconnection control unit that disconnects the second device from the first device.

(Operation) The present invention relates to an IC of a receiving apparatus main body.
The test signal is multiplexed to the broadcast signal at the card input unit, the test signal is detected at the output of the IC card, the failure of the IC card is determined, and the signal is switched by a switch so as to bypass the IC card determined to be defective. By disconnecting the card from the system, the I
By resetting the C card and the circuit, it is possible to prevent a large influence on the entire receiving system.

Further, by displaying the details of the failure detection, the user can know the details of the failure, and can immediately cope with the failure.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings, but the description of the same parts as those described in the conventional example will be omitted. FIG. 1 is a block circuit diagram illustrating a configuration of a digital broadcast receiving apparatus according to a first embodiment of the present invention.

In FIG. 1, a digital broadcast receiving apparatus 1
Is composed of a receiving device main body 3 and IC cards 5 and 7. Although the example of FIG. 1 shows a case where there are two IC cards, the same applies to one IC card or three or more IC cards.

The receiving apparatus main unit 3 includes an input terminal 1004 to which a broadcast wave is input, an external input terminal 1005, a tuner / demodulation circuit 1006, an error correction circuit 1007, and a test for multiplexing a test signal with a broadcast signal to form a test input signal. Signal multiplexing circuit 101, switches 1008, 1009, 1010,
1011, 1012, a test signal detection circuit 102 for detecting a test output signal from a broadcast signal, a DEMUX circuit 101
3. A video / audio decoding circuit 1014, an on-screen circuit 103, a video / audio output circuit 1015, an output terminal 1016 to a television receiver, a control circuit 1017 for controlling a test of a receiving device main body and an IC card, a card detection circuit 1018, 1019 It has.

The IC card 5 includes a signal processing circuit 1020 for performing signal processing specific to each IC card, such as descrambling and text broadcast decoding, on a broadcast signal;
21. The IC card 7 includes a signal processing circuit 1022 for performing signal processing specific to each IC card, such as descrambling and teletext decoding, on a broadcast signal, and a control circuit 1023.

The receiving apparatus main body 3 includes, for example, a test signal multiplexing circuit 101 and a conventional receiving apparatus main body 1001 shown in FIG.
A test signal detection circuit 102 and an on-screen circuit 103 are added. Other configurations are almost the same as those of the conventional digital broadcast receiving apparatus.

The test signal multiplexing circuit 101 is a circuit that multiplexes a test signal with a broadcast signal after a transmission error has been corrected by the error correction circuit 1007 and uses the multiplexed test signal as a test input signal for each IC card. The test signal detection circuit 102 is a circuit for detecting a test output signal from a broadcast signal returned to the receiving device main body 3 from the last stage of one or more daisy-chained IC cards.

When the test signal detection circuit 102 cannot detect the test signal, the on-screen circuit 103
This is a circuit for determining that a card has failed and displaying the content of the determination on a television screen.

The IC cards 5 and 7 are exactly the same as conventional IC cards. Test signal multiplexing circuit 1
01 multiplexes the test signal with the broadcast signal after the transmission error is corrected by the error correction circuit 1007. This test signal may be read out from a test signal storage unit (not shown) provided inside the test signal multiplexing circuit 101 and multiplexed with a broadcast signal, or may be read out from the test signal multiplexing circuit 101 under the control of the control circuit 1017. It may occur internally. Alternatively, data may be read from a storage unit (not shown) provided inside the control circuit and supplied to the test signal multiplexing circuit 101. The test signal includes a specific constant or a random number.

FIG. 2 is a diagram for explaining how a test signal is multiplexed. A broadcast signal 201 in FIG. 2A shows a data format of a general broadcast signal. Broadcast signal 20
1 is a synchronization signal (SYNC) 202, a payload 203,
One packet is formed by an error correction code (ECC) 204, and a broadcast signal 201 is formed from a series of packets. Here, the error correction circuit 1007 in FIG. 1 performs an error correction operation based on the payload 203 and the error correction code 204, corrects an error in transmission data, and outputs it to a subsequent stage.

That is, the error correction code 204 of the signal after error correction becomes invalid. Mask signal 2 in FIG.
Reference numeral 05 denotes a mask signal indicating an invalid portion (H level) of the broadcast signal 201. The broadcast signal 201 shown in FIG.
The test signal is multiplexed as indicated at 06. FIG. 2 shows an example in which the test signal 207 is multiplexed in the invalid portion.

The multiplexed test signal includes a specific constant, a random number and the like. The broadcast signal 206 multiplexed with the test signal 207 and the mask signal 205
1009, a signal processing circuit (descrambler) 1020 in the IC card 5, switches 1010 and 1011, a signal processing circuit (descrambler) 1022 in the IC card 7,
The signal is propagated to the subsequent stage on the path of the switch 1012.

The broadcast signal 20 in which the test signal 207 is multiplexed
6 and the mask signal 205 are the switches 1008 and 1009
Is sent to the IC card 5 via. In IC card 5,
The test signal is output without any processing, and the signal processing circuit 1020 performs, for example, a descrambling process on the broadcast signal, multiplexes them, and inputs one of the switches 1010 of the receiving device body 3. Returned as a signal.

The broadcast signal returned to one input of the switch 1010 is output from the switch 1010 to the switch 1010.
The data is output to the IC card 7 via the IC card 11. IC card 7
Then, the same processing as that of the IC card 5 is performed, and the processing is returned as one input signal of the switch 1012 of the receiving apparatus main body 3.

The output of the switch 1012 is connected to the input of the test signal detection circuit 102. The test signal detection circuit 102 detects the test signal portion from the broadcast signal and sends the detection signal 104 to the control circuit 1017. The normal broadcast signal portion other than the test signal is sent to the subsequent DEMUX circuit 1013, and the same processing as in the related art is performed.

The test signal detection circuit 102 is a circuit for determining whether or not the test output signal sent from the last stage of the IC card is a correct test signal to determine the normality of the IC card. The test signal read from the built-in storage unit or the test signal generated internally is compared with the test output signal sent from the switch 1012, the normality of the IC cards 5 and 7 is determined, and the detection signal 10 is sent to the control circuit 1017.
At step 4, the detection result is transmitted.

The control circuit 1017 receiving the detection signal 104
Is used to disconnect the IC card determined to be abnormal from the receiving device main unit 3 or the IC card at the subsequent stage of the IC card determined to be abnormal and / or the I
The circuit section subsequent to the C card is reset by the RESET signal 105.

The control circuit 1017 notifies the on-screen circuit 103 of the test result, and the on-screen circuit 1
In step 03, a message for displaying the contents of the normality test result as shown in FIG. 6 is assembled on the video signal and displayed on the TV screen.

Next, the operation of the first embodiment will be described with reference to the flowchart of FIG. In step S301, the test signal is transmitted to the broadcast signal 20 using the test signal multiplexing circuit 101.
Multiplex to 1. In step S302, a test signal is detected from the broadcast signal 206, and determination is made in step S303. If the test signal is normal, the IC card is regarded as normal, and the process ends. If the test signal cannot be detected or cannot be determined as a correct test signal in step S303, the IC card is regarded as abnormal, and step S304 is performed.
The switch 1010 or 1012 is switched to bypass the IC card, and the switch 1009 or 1011 is switched to open.

As a result, the IC card is separated from the receiving device main body 3. Next, in step S305, a message as shown in FIG. 6 is displayed on the screen by the on-screen circuit 103. Here, in the embodiment, the example using the on-screen circuit has been described, but a lamp display such as an LED provided on a panel surface of a receiving device main body (not shown) may be used. Further, in step S307, a RESET signal 105 is output from the control circuit 1017 and the DEMUX circuit 10
13. Reset the subsequent circuit such as the video / audio decoding circuit 1014 or the IC card.

Next, a second embodiment will be described with reference to the block diagram of FIG. 1 and the flowchart of FIG. First, a variable N is initialized to 1 in step S401. Variable N
Is a variable indicating the slot of the IC card, and the slots of the IC card are numbered from 1 to the number of slots. In step S402, the card detection circuit 1018 or 1019 detects whether or not the IC card is inserted into the receiving device main body. If not, the process of determination is skipped. If it is inserted, a determination process is performed.

In step S403, the IC card slot N
Is connected, and the other switches are set to the unconnected state. For example, the IC card 5 is inserted,
When making a determination, the switch 1009 is set to the connection side, the switch 1010 is set to the IC card output side, the switch 1011 is set to the open side, and the switch 1012 is set to the bypass side of the IC card, and the determination is made only for the IC card 5. . From step S404 onward, the same processing as that of the determination processing of FIG. 3 is performed for one IC card. If it is determined that the IC card is normal, the result flag R (N) is set to 0 in step S407, and it is determined that the IC card is abnormal. In this case, R (N) is set to 1 in step S408. Next, step S
409, in step S410, N is incremented by 1 to determine the next IC card. If N exceeds the number of IC card slots, a series of determination processing ends, and N
If the number is equal to or less than the number of card slots, the same determination is made for the next IC card.

The IC card slot finally determined to be abnormal based on the value of R (N) is the same as that of FIG.
By operating a switch for outputting a broadcast signal to the C card slot and a switch for bypassing the IC card slot, the IC card is separated from the main body of the receiving apparatus (step S412), and the contents determined to be abnormal are determined by the on-screen circuit 103. It is displayed on the TV screen (step S413), and the process of resetting the subsequent circuit of the IC card determined to be abnormal (step S414) is performed.

FIG. 5 is a block diagram illustrating the configuration of a third embodiment of the digital broadcast receiving apparatus according to the present invention. In FIG. 5, each IC in the receiving device main body 3
A test signal multiplexing circuit 101 is provided at an input portion of the card, and a test signal detection circuit 102 is provided at an IC card output portion. In the illustrated example, the test signal detection circuit 102 is provided at the input of the switch 1010 or the switch 1012, but may be provided at the output of the switch 1010 or the switch 1012. The determination process and the switch control process are performed for each IC card in the same manner as in the first embodiment.

[0044]

As described above, according to the present invention, the failure of the IC card is determined by multiplexing the test signal with the broadcast signal, and the determined failure of the IC card is separated from the main body of the receiving apparatus. The influence can be limited to the function of the IC card, and the influence on the entire receiving system can be prevented.

Further, by displaying the details of the failure detection, the user can know the details of the failure, and can immediately cope with the failure.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to first and second embodiments of the present invention.

FIG. 2 is a configuration example of a signal for explaining a test signal insertion position in the first embodiment.

FIG. 3 is a flowchart illustrating the operation of the first embodiment.

FIG. 4 is a flowchart illustrating the operation of the second embodiment.

FIG. 5 is a block diagram showing a configuration of a digital broadcast receiving apparatus according to a third embodiment of the present invention.

FIG. 6 is an example of a message displayed on the screen for failure notification in the present invention.

FIG. 7 is a block diagram showing a configuration of a conventional digital broadcast receiving apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Digital broadcast receiver, 3 ... Receiver main body, 5 ... I
C card, 7 IC card, 101 test signal multiplexing circuit, 102 test signal detection circuit, 103 on-screen circuit, 104 detection signal, 105 RESET signal,
1004 terminal, 1005 terminal, 1006 tuner / demodulation circuit, 1007 error correction circuit, 1008, 10
09, 1010, 1011, 1012 ... switch, 10
13: DEMUX circuit, 1014: video / audio decoding circuit, 1015: video / audio output circuit, 1016 ... output terminal, 1017 ... control circuit, 1018, 1019 ... card detection circuit, 1020, 1022 ... signal processing circuit, 102
1, 1023 ... Control circuit.

Claims (7)

[Claims] 1. A signal obtained by receiving and demodulating a digital broadcast in a first device, or a demodulated packet format broadcast signal provided from a signal supply device external to the first device,
Daisy-chained 1s via the first device
Output to one or more second devices, perform signal processing on the input signal in the second device, output again to the first device, and decode and output the signal after signal processing in the first device A control method in a digital broadcast receiving apparatus, comprising: multiplexing a test signal with a broadcast signal in a stage preceding the second apparatus; detecting a test signal output from the second apparatus in the first apparatus; A control method characterized in that the second device is disconnected based on a result of the detection. 2. A signal obtained by receiving and demodulating a digital broadcast in a first device, or a broadcast signal in a packet format demodulated from a signal supply device external to the first device.
Output to one or more second devices that can be separated from the first device, perform signal processing on the input signal in the second device, and then output again to the first device; A digital broadcast receiving device that decodes and outputs a signal after signal processing in the device, a connection unit that daisy-chain connects one or more of the second devices, and a test signal is added to the broadcast signal at a stage preceding the second device. Test signal multiplexing means for multiplexing; test signal detecting means for detecting a test signal output from the second device in the first device; a signal bypassing the second device; One or more switch means for switching between an output signal and the test signal detecting means, when the test signal cannot be detected, controlling the switch means to disconnect the second device from the first device. Digital broadcast receiving apparatus characterized by comprising a to disconnection controlling means. 3. A signal obtained by receiving and demodulating a digital broadcast in a first device, or a demodulated packet-format broadcast signal provided from a signal supply device external to the first device,
Output to one or more second devices that can be separated from the first device, perform signal processing on the input signal in the second device, and then output again to the first device; A digital broadcast receiving device that decodes and outputs a signal after signal processing in the device, a connection unit that daisy-chain connects one or more of the second devices, and a test signal is added to the broadcast signal at a stage preceding the second device. Test signal multiplexing means for multiplexing; test signal detecting means for detecting the test signal output from the second device in the first device; a signal bypassing the second device; and the second device One or more switch means for switching between the first and second output signals; and connection control means for sequentially controlling the one or more switch means to sequentially connect the second device to the first device. Digital broadcast receiving apparatus, characterized in that said test signal means is provided with a disconnection control means for disconnecting from said first device the second device by controlling the switch means when the undetectable. 4. A signal obtained by receiving and demodulating a digital broadcast in the first device or a broadcast signal in a packet format provided from a signal supply device external to the first device.
Outputting the signal to one or more second devices that can be separated from the first device, performing signal processing on the input signal in the second device, outputting the signal again to the first device, A digital broadcast receiving apparatus for decoding and outputting a signal after signal processing in the apparatus, a connection means for daisy-chaining one or more of the second apparatuses, and an input unit of each of the second apparatuses in the first apparatus A test signal multiplexing unit that multiplexes a test input signal with a broadcast signal, a test signal detection unit that detects a test signal multiplexed on the broadcast signal at an output unit of each of the second devices in the first device, One or more switch means for switching between a signal bypassing the second device and an output signal of the second device; and a switch when the test signal detecting means cannot detect the test signal. Controls pitch means, said digital broadcast receiver a second apparatus is characterized in that anda disconnection control means for disconnecting from said first device. 5. A first reset means for resetting the plurality of second devices connected in a daisy chain, connected to at least a subsequent stage of the second device in which a test signal is not detected by the test signal detecting means. The digital broadcast receiving apparatus according to any one of claims 2 to 4, further comprising: control means for resetting the second device by the first reset means. . 6. A second reset means for resetting a circuit portion of the first device connected to a subsequent stage of the plurality of second devices connected in a daisy chain, and a test signal is detected by the test signal detecting means. The digital broadcast receiving apparatus according to any one of claims 2 to 4, further comprising: control means for resetting by the second reset means when no signal is detected. 7. The apparatus according to claim 2, further comprising display means for displaying an abnormality of said second device when said test signal is not detected by said test signal detection means. The digital broadcast receiving device according to the item.