JPH077276U - Satellite broadcasting receiver - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to cancel video mute in independent audio mode when switching to external input mode such as descrambler in satellite broadcasting receiver that automatically mutes video in independent audio. To do. [Structure] When a video signal from an external device such as the descrambler 50 is input, this is input to a mode detection circuit 60.
Detects the video mute and controls the microcomputer (control means) 17 to cancel the video mute, the video mute state is automatically canceled even if the video mute is already applied by the independent audio selection, and the descrambler video signal is output. Can be captured inside the receiving device 10 and displayed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a satellite broadcast receiver, and in particular, even when the audio output mode of BS broadcast or CS broadcast is switched to independent audio, when a video signal is input from an external device such as a descrambler, video mute is performed. The present invention relates to a satellite broadcast receiving device that prevents operation.

[0002]

[Prior art]

 In the television broadcasting of BS and CS, as audio signals, information of 4 channels in total, that is, A mode television audios 1, 2 and independent audios 1, 2 are transmitted. Television sounds 1 and 2 are audio information associated with television broadcasting, and independent sounds 1 and 2 are independent information different from the contents of television broadcasting. On the receiving side, these two types of audio information can be switched by user control.

Consider a case where a receiving device such as a television set or a VTR receives a BS broadcast or a CS broadcast having independent audio. In this case, when the user listens to or records the independent audio, it is not necessary to output or output the TV image, so it is conceivable that the video mute will be applied automatically.

FIG. 3 is a circuit diagram showing a conventional satellite broadcast receiving device of a specification in which video mute is automatically performed during such independent audio. In FIG. 3, the satellite broadcast receiving device 10 has an input terminal 11 with a switch for externally inputting a video signal, and the video output from the descrambler 50 which is an external device can be connected to the input terminal 11. . In the switch-equipped input terminal 11, when the external terminal is not inserted, the internal switch contacts 11a and 11b are in a conductive state (on), and when the external terminal is inserted, they are in a non-conductive state (off). A detection output from an FM detection circuit (not shown) inside the receiving device is supplied to the one switch contact 11a as an internal image output after being reduced in the high frequency range by the de-emphasis circuit 12 and through the coupling capacitor 13. Therefore, by inserting the external terminal, the internal video output from the de-emphasis circuit 12 is switched to the video output from the descrambler 50 and output. The output at the switch contact position b of the input terminal 11 is input to the video mute circuit 16 via the coupling capacitor 15.

The video mute circuit 16 supplies or blocks the video output from the switch contact 11b to the next stage circuit inside the receiving device via the drain / source path of the field effect transistor (FET) 21. , The voltage of the DC power supply Vcc divided by the resistors 28 and 29 is supplied to the drain and the source of the FET 21, respectively, through the resistors 24 and 23, and the voltage of the DC power supply Vcc is supplied to the gate of the FET 21. Is supplied via a resistor 25, while its gate is connected to a reference potential point via the collector-emitter path of the transistor 22, and the base of the transistor 22 is supplied from a microcomputer (hereinafter, microcomputer) 17 to a low level (L). Alternatively, a high level (H) mute control signal is supplied. When the high-level mute control signal is input, the video mute circuit 16 turns on the transistor 22 and turns off the FET 21 to mute the video signal.

The microcomputer 17 generates various control signals. When the user presses a voice output mode switching key of a key input means (not shown), a TV / independent (TV / independent) switching signal is sent to the PCM demodulation circuit 18. It is supplied and switched between TV sound and independent sound. The microcomputer 17 outputs a high level mute control signal to the video mute circuit 16 at the same time as outputting the switching signal between the television sound and the independent sound. That is, in the independent audio mode, the microcomputer 17 switches the PCM demodulation circuit 18 to the independent audio and at the same time outputs a high level mute control signal to the video mute circuit 16 to automatically mute the video. The key input means (not shown) connected to the microcomputer 17 has a video mute key, and the video mute can be independently executed regardless of the audio output mode switching.

Here, in a state where the output terminal of the descrambler 50 is not inserted into the input terminal 11, the internal video output is taken in through the video mute circuit 16. At this time, the audio output mode is switched to the independent audio by the key input, and at the same time, the high level mute control signal is output to the video mute circuit 16 to perform the video mute. Next, when the external video output is supplied to the video mute circuit 16 by inserting the terminal of the descrambler 50 into the input terminal 11, the descrambler video output cannot be taken inside because the video mute state has already been entered. Cause problems.

FIG. 4 shows another conventional example of a satellite broadcast receiving device of a specification in which video mute is automatically performed during independent audio. In FIG. 4, the satellite broadcast receiving device 10 has an input terminal 11A for externally inputting a video signal, and the video output from the descrambler 50 which is an external device can be connected to the input terminal 11A. A switch circuit 19 for switching between internal video output and external video output is provided inside the receiving device. The detection output from an FM detection circuit (not shown) inside the receiver is supplied to one input terminal a of the switch circuit 19 as an internal image output after being reduced in the high frequency range by the de-emphasis circuit 12 and through the coupling capacitor 13. . The external video output from the input terminal 11A is supplied to the other input terminal b of the switch circuit 19 via the circuit of the resistor 31 and the coupling capacitor 32. At the same time, the external video output from the input terminal 11A is supplied to the signal detection circuit 20 via the circuit of the resistor 31 and the coupling capacitor 32 and the coupling capacitor 33.

In the signal detection circuit 20, the external video output is supplied to the base of the emitter follower transistor 34, the emitter of the transistor 34 is connected to the reference potential point via the resistor 37, and the collector is connected to the DC power supply Vcc. The base is supplied with the voltage at the connection point of the resistors 35 and 36 connected in series between the DC power supply Vcc and the reference potential point, and the emitter of the transistor 37 is supplied to the base of the transistor 42 via the capacitor 38 and the resistor 39. The base of the transistor 42 is connected to the DC power source Vcc via the capacitor 40, and is connected to the reference potential point via the resistor 41. The emitter of the transistor 42 is connected to the DC power supply Vcc, the collector is connected to the reference potential point via the resistor 43, and the collector is connected to the reference potential point via the voltage dividing resistors 44 and 45. Is connected to the base of the transistor 47 via the Zener diode 46, the emitter of the transistor 47 is connected to the reference potential point, and the collector of the transistor 47 is connected to the DC power supply Vcc via the resistor 48, while its collector output is The signal is supplied to the switching control terminal of the switch circuit 19 as a switching signal.

The output terminal c of the switch circuit 19 is input to the video mute circuit 16 via the coupling capacitor 15. Similar to FIG. 3, the video mute circuit 16 includes a field effect transistor (FET) 21 that turns on / off the passage of a video output, and a transistor 22 that is connected to the gate of the FET 21 to control the on / off of the FET. , And bias resistors 23 to 29. A low-level or high-level mute control signal is supplied from the microcomputer 17 to the base of the transistor 22. Similar to FIG. 3, the microcomputer 16 also generates various control signals. When the user presses the audio output mode switching key of the key input means (not shown), the switching signal (TV / TV / independent audio) is switched. An independent switching signal) is supplied to the PCM demodulation circuit 18 to switch between television sound and independent sound. Simultaneously with the switching between the television sound and the independent sound, the microcomputer 17 outputs the mute control signal to the image mute circuit 16 to automatically mute the image. Also in this case, there is a video mute key in the key input means connected to the microcomputer 17, and it is possible to execute the video mute independently regardless of switching the video output mode.

In the circuit of FIG. 4, when the external terminal of the descrambler 50 is inserted into the input terminal 11 A, the descrambler video output is input to the input terminal b of the switch circuit 19 and also to the signal detection circuit 20. It In the signal detection circuit 20, the external video output is input to the integration circuit of the resistor 39 and the capacitor 40 via the emitter follower transistor 34, the negative integration signal turns on the transistor 42, and the voltage obtained at its collector By supplying the voltage divided by 44 and 45 to the transistor 47 through the Zener diode 46, the transistor 47 is turned on and a low level switching signal is output from the collector. As a result, the switch circuit 19 is switched to the input terminal b. In this way, the output of the signal detection circuit 20 switches between low level and high level depending on the presence or absence of the video signal from the descrambler 50, which causes the switch circuit 19 to switch between the input terminals b and a. As a result, when there is a signal input from the input terminal 11A, the external video output is taken in through the video mute circuit 16, and when there is no signal, the internal video output is taken in through the video mute circuit 16 internally. Here, when the switch circuit 19 selects the internal video output, when the audio output mode is switched to the independent audio by the key input, the high-level mute control signal is input to the video mute circuit 16 and the FET 21 is turned on. Turned off and video mute is applied. Next, when the descrambler 50 is inserted into the input terminal 11A and the external video output is supplied to 11A, the signal detection circuit 20 detects this and switches the switch circuit 19 to the input terminal b side, but the video mute circuit 16 There is a problem that the descrambled video output cannot be captured internally because it is in the mute state due to the independent audio selection.

As described above, when the descrambler 50 is connected to the input terminal 11 or 11 A of the receiving device 10 and the video output of the receiving device 10 is the signal output from the descrambler 50, TV / independent audio is output. I cannot operate the switch key. That is, if the video mute described above is linked only to the independent audio mode of the receiving device, when the receiving device such as the television set or the VTR is set to the independent audio mode, the external image is not output and the audio of the television broadcast is output. The problem occurs that only the output is made. To solve this problem, video mute should not be applied in the output mode by the descrambler.

However, when the switching of the image output mode of the internal video output or the external video output is manual switching on the user side, if the microcomputer is controlled in conjunction with the manual switching, the above-mentioned solution is This can be easily achieved by only changing the software, but as shown in Fig. 3 and Fig. 4, when the output mode switching is automatically performed by detecting the insertion of the terminal of the descrambler or the signal detection of the external video input, Since image mode switching does not depend on the control of the microcomputer, it is not possible to release the image mute with only the microcomputer software.

[0014]

[Problems to be solved by the device]

 As described above, in a receiver that automatically switches to the descramble mode by detecting the terminal insertion of the descrambler or detecting the signal, if you try to cancel the video mute of the independent audio in the descramble mode, only the software is required. There was a problem that we could not respond.

In view of the above-mentioned problems, the present invention provides a satellite that can cancel video mute of independent audio in a descramble mode in a receiver that automatically switches to a descramble mode with a simple circuit. It is intended to provide a broadcast receiving device.

[0016]

[Means for Solving the Problems]

 In the satellite broadcasting receiving apparatus according to the present invention as set forth in claim 1, an input terminal to which an external video signal is input, an externally input video signal from this input terminal and a video signal demodulated inside the receiving apparatus are connected. Switch means for outputting either one of them, a video mute circuit for muting the output of this switch means, and control for switching the audio output mode of the receiving device between television audio and independent audio. Control means for controlling the video mute circuit to perform a mute operation when the switch is switched to independent audio, and whether or not the output mode of the switch means is external input, and when the external input is detected, the receiving device is detected. A signal for canceling the mute operation of the video mute circuit is output to the control means even when the audio output mode is independent audio. And a mode detection circuit that operates.

[0017]

[Action]

 In the present invention, when a video signal from an external device such as a descrambler is input, the mode detection circuit detects it and controls the control means (microcomputer) to cancel the video mute. Even if the video mute is set by the independent audio selection, the video mute state is automatically released, and the descrambler video signal can be captured and displayed inside the receiver.

[0018]

【Example】

 Examples will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a satellite broadcast receiving apparatus according to an embodiment of the present invention. The same parts as those in FIG.

In FIG. 1, the satellite broadcast receiving apparatus 10 has an input terminal 11 with a switch for externally inputting a video signal, and a video output from a descrambler 50 which is an external apparatus can be connected to the input terminal 11. Has become. When the external terminal is not inserted, the switch-equipped input terminal 11 has internal switch contacts 11a and 11b turned on, and is turned off by inserting an external terminal. The detection output from an FM detection circuit (not shown) inside the receiving device is supplied to the one switch contact 11a as an internal image output after being reduced in the high frequency range by the de-emphasis circuit 12 and through the coupling capacitor 13. Therefore, by inserting the external terminal, the internal video output from the de-emphasis circuit 12 is switched to the video output from the descrambler 50 and output. The output of the switch contact 11b of the input terminal 11 is input to the video mute circuit 16 via the coupling capacitor 15.

The video mute circuit 16 supplies or blocks the video output from the switch contact 11b to the next stage circuit inside the receiver via the drain / source path of the field effect transistor (FET) 21. , The drain and source of the FET 21 are supplied with the voltage obtained by dividing the voltage of the DC power supply Vcc by the resistors 28 and 29 through the resistors 24 and 23, and the voltage of the DC power supply Vcc is fed to the gate of the FET 21. Is supplied via the resistor 25, while the gate is connected to the reference potential point via the collector-emitter path of the transistor 22, so that the base of the transistor 22 is supplied with the mute control signal from the microcomputer 17. Has become.

The microcomputer 17 generates various control signals, and when the user presses a voice output mode switching key of a key input means (not shown), a television / independent switching signal is supplied to the PCM demodulation circuit 18, and a television audio signal is supplied. And independent voices are switched. The microcomputer 17 outputs the mute control signal to the video mute circuit 16 at the same time as switching between the television sound and the independent sound. That is, in the independent audio mode, the microcomputer 17 switches the PCM demodulation circuit 18 to the independent audio and simultaneously outputs a high-level mute signal to the video mute circuit 16 to automatically mute the video. Note that the key input means connected to the microcomputer 17 has a video mute key, and the video mute can be executed independently regardless of the switching of the audio output mode.

In addition to the above configuration, in the present embodiment, the mode detection circuit 60 is provided by connecting to the line connecting the coupling capacitor 13 and the switch contact 11a of the input terminal 11. The mode detection circuit 60 detects whether the terminals of the descrambler 50 are inserted in the input terminal 11 by detecting the on / off states of the switch contacts 11a and 11b of the input terminal 11. In the mode detection circuit 60, the switch contact 11a is connected to the base of the transistor 61, the collector thereof is connected to the reference potential point, the emitter is connected to the DC power source Vcc through the resistor 64, and the base of the transistor 61 is It is connected to the connection point of resistors 62 and 63 connected in series between the DC power source Vcc and the reference potential point, and the emitter of the transistor 61 is connected to the reference potential point via the resistor 65. It is configured to be connected to the video mute release terminal of the computer 17 through an integrating circuit.

Next, the operation of FIG. 1 will be described. When the descrambler 50 is not connected to the input terminal 11, the switch contacts 11a and 11b of the input terminal 11 are conductively connected to each other, and therefore the resistance of the bias resistor 63 of the transistor 61 of the mode detection circuit 60 is reduced. 14 are connected in parallel, the base bias resistance of the transistor 61 is set to a low value, the base potential is set to a low value, the transistor 61 is turned on, and the emitter potential becomes low level. The emitter output is smoothed by the resistor 66 and the capacitor 67 and input to the microcomputer 17. At this time, the microcomputer 17 does not control the operation of the video mute circuit 16 even if it receives the low level signal from the mode detection circuit 60.

When the output terminal of the descrambler 50 is inserted into the input terminal 11, the connection state between the switch contacts 11a and 11b is released, and as a result, the base bias resistance of the transistor 61 of the mode detection circuit 60 is only the resistance 63. Therefore, at this time, the base potential is set high, the transistor 61 is turned off, the emitter potential becomes high level, smoothed by the resistor 66 and the capacitor 67, and a high level signal is input to the microcomputer 17. At this time, if the independent audio mode is specified for the microcomputer 17 in advance (that is, the high-level (H) mute control signal is supplied to the transistor 22 of the video mute circuit 16), the microcomputer Numeral 17 forcibly sets the mute control signal to the video mute circuit 16 to the low level (L) by the high level signal from the above mode detection circuit 60, and automatically releases the video mute state in the independent audio mode. To do.

FIG. 2 is a circuit diagram showing a satellite broadcast receiving apparatus according to another embodiment of the present invention. The same parts as those in FIG. 4 will be described with the same reference numerals.

In FIG. 2, the satellite broadcast receiving apparatus 10 has an input terminal 11 A for externally inputting a video signal, and a video output from a descrambler 50 which is an external device can be connected to the input terminal 11 A. There is. A switch circuit 19 for switching between internal video output and external video output is provided inside the receiving device. A detection output from an FM detection circuit (not shown) inside the receiver is supplied to one input terminal a of the switch circuit 19 as an internal image output after being subjected to high frequency reduction by the de-emphasis circuit 12 and passing through the coupling capacitor 13. . The external video output from the input terminal 11A is supplied to the other input terminal b of the switch circuit 19 via the circuit of the resistor 31 and the coupling capacitor 32. At the same time, the external video output from the input terminal 11A is supplied to the signal detection circuit 20 via the circuit of the resistor 31 and the coupling capacitor 32 and the coupling capacitor 33.

In the signal detection circuit 20, the external image output is supplied to the base of the emitter follower transistor 34, the emitter of the transistor 34 is connected to the reference potential point via the resistor 37, and the collector is connected to the DC power supply Vcc. The base is supplied with the voltage at the connection point of the resistors 35 and 36 connected in series between the DC power supply Vcc and the reference potential point, and the emitter of the transistor 37 is supplied to the base of the transistor 42 via the capacitor 38 and the resistor 39. The base of the transistor 42 is connected to the DC power source Vcc via the capacitor 40, and is connected to the reference potential point via the resistor 41. The emitter of the transistor 42 is connected to the DC power supply Vcc, the collector is connected to the reference potential point via the resistor 43, and the collector is connected to the reference potential point via the voltage dividing resistors 44 and 45. Is connected to the base of the transistor 47 via the Zener diode 46, the emitter of the transistor 47 is connected to the reference potential point, and the collector of the transistor 47 is connected to the DC power supply Vcc via the resistor 48, while its collector output is It is adapted to be supplied as a switching control signal to the switching control terminal of the switch circuit 19.

The output terminal c of the switch circuit 19 is input to the video mute circuit 16 via the coupling capacitor 15. The video mute circuit 16 is similar to FIG. 1 in that it has a field effect transistor (FET) 21 for turning the video output on and off, a transistor 22 connected to the gate of the FET 21 for controlling the on and off of the FET, and a bias. It is composed of resistors 23 to 29. A mute control signal is supplied to the base of the transistor 22 from the microcomputer 17A. Similarly to FIG. 1, the microcomputer 17A also generates various control signals, and the user presses the audio output mode switching key of the key input means (not shown) to switch the TV audio and independent audio switching signals ( (TV / independent switching signal) is supplied to the PCM demodulation circuit 18 to switch between television sound and independent sound. Simultaneously with the switching between the television sound and the independent sound, the microcomputer 17A outputs the mute control signal to the video mute circuit 16 and automatically mutes the video. The key input means connected to the microcomputer 17A has a video mute key, and the video mute can be independently executed regardless of the audio output mode switching.

In addition to the above configuration, in this embodiment, the output of the signal detection circuit 20 is also input to the video mute release terminal of the microcomputer 17A. At this time, the signal detection circuit 20 also operates as a mode detection circuit (a circuit that detects whether or not the video signal from the descrambler 50 is input to the input terminal 11A).

Next, the operation of FIG. 2 will be described. The specific operations of the video mute circuit 16 and the signal detection circuit 20 are the same as in the case of FIG. When the video output from the descrambler 50 is input to the input terminal 11A, the output of the signal detection circuit 20 becomes low level and the switch circuit 19 is switched to the input terminal b side to supply the external video output to the video mute circuit 16. . At this time, the low level signal of the signal detection circuit 20 is also supplied to the video mute release terminal of the microcomputer 17A, which causes the microcomputer 17A to output a low level signal to the video mute circuit 16 forcibly releasing the video mute. Input the level signal to cancel the video mute state. Therefore, when the independent audio mode is designated in advance for the microcomputer 17A (that is, when the high-level (H) mute control signal is supplied to the transistor 22 of the video mute circuit 16), the microcomputer 17A A mute control signal for the video mute circuit 16 is forcibly set to a low level (L) by a low level signal from the signal detection circuit 20 to automatically cancel the video mute state in the independent audio mode. it can. In this embodiment, the microcomputer 17A does not control the operation of the video mute circuit 16 even if it receives the high level signal from the signal detection circuit 20.

In the above embodiment, the video signal externally input to the satellite broadcast receiving apparatus 10 is the video signal from the descrambler 50. However, in the present invention, the externally input video signal apparatus is limited to the descrambler. It is not something that will be done.

[0032]

[Effect of device]

 As described above, according to the present invention, in a receiving device that automatically mutes video in the independent audio mode, when the external input such as a descrambler is switched, the video muting in the independent audio mode is automatically canceled. It becomes possible. Moreover, it can be realized with a simple circuit.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a satellite broadcast receiving apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a satellite broadcast receiving device according to another embodiment of the present invention.

FIG. 3 is a circuit diagram showing a conventional satellite broadcast receiving device.

FIG. 4 is a circuit diagram showing another conventional satellite broadcast receiving device.

[Explanation of symbols]

 10 ... Satellite broadcasting receiver 11 ... Input terminal with switch 11A ... Input terminal 16 ... Video mute circuit 17, 17A ... Microcomputer (control means) 19 ... Switch circuit 20 ... Signal detection circuit 50 ... Descrambler 60 ... Mode detection circuit

Claims (1)

[Scope of utility model registration request] 1. An input terminal to which an external video signal is input, a switch to which the externally input video signal and the video signal demodulated inside the receiving device are connected, and one of which is output. Means, a video mute circuit for muting the output of the switch means, and control for switching the audio output mode of the receiving device between television audio and independent audio, while the audio output mode is switched to the independent audio. Control means for controlling the video mute circuit to perform a mute operation, and whether or not the output mode of the switch means is an external input, and when the external input is detected, the audio output mode of the receiving device is an independent audio. And a mode detection circuit for outputting a signal for canceling the mute operation of the video mute circuit to the control means. Satellite broadcasting receiver to collect.