JPH10210387A - Voice-muting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform on/off control of a voice-muting device in the accurate timing, in order not to give unpleasant feeling to a viewer. SOLUTION: A down-data demodulator demodulates the down-data modulated signal 16 transmitted from a center via a data/only channel to obtain a down- data signal 17, containing the broadcast form information which shows the number of every receivable channel and also shows whether the relevant channel is equal to an analog or digital broadcast signal channel. Then the channel data 18, consisting of every receivable channel number and the broadcast from information contained in the signal 17, are stored in a channel memory 2. The channel number shown by the inputted channel select signal 19 is compared with the data 18 to decide whether the selected channel belongs to an analog or digital broadcasting. The delay time of a voice muting device 13 is controlled based on this decision result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio mute device used in a receiver capable of receiving a digital broadcast signal and an analog broadcast signal in a transmission infrastructure in which a digital broadcast signal and an analog broadcast signal are mixed. Things. Currently, satellite digital broadcasting, which has actually started broadcasting, is not configured to be able to receive it with the same receiving terminal as existing satellite analog broadcasting, and the broadcasting side also performs analog / digital transmission on the same satellite. Although the system is not a mixed system, it is effective when analog broadcast signals and digital broadcast signals are mixed. For example, in the case of CATV, when considering a system in which an analog transmission channel using an existing analog modulation wave and a digital broadcasting channel using a digital modulation wave such as 64QAM are mixed in one coaxial cable, both of them are considered. This is effective in a receiving terminal capable of receiving.

[0002]

2. Description of the Related Art Conventional receivers such as a television receiver, a CATV terminal, and a satellite broadcast terminal will be described below with reference to FIG. In FIG. 2, 5 is a tuner, 6 is an analog broadcast signal detection / demodulation unit, 13 is an audio muting device,
38 is a controller. In this prior art receiver, the channel data signal 19 is selected by the controller 3.
When input to 8, the controller 38 provides the tuner 5 with a channel selection signal 20 corresponding to the data indicated by the channel data signal 19. As a result, the tuner 5 performs channel selection in response to the channel selection signal 20. At this time, the tuner 5 transmits the analog broadcast RF
An (high frequency) signal 21 'is input, and an analog broadcast IF (intermediate frequency) signal 22' corresponding to the selected channel is output. Then, the analog broadcast IF signal 22 ′ is supplied to the analog broadcast signal detection / demodulation unit 6, and the analog broadcast signal detection / demodulation unit 6 outputs an analog baseband audio signal 23 and an analog baseband video signal 24. In this case, the analog baseband audio signal 23 is input to the audio mute unit 13 once.

When the analog baseband video signal 24 to be demodulated is stabilized, the analog broadcast signal detection / demodulation section 6 outputs an analog demodulation stable signal 35 and supplies it to a controller 38. As a result, the controller 38 applies a predetermined mute to the analog baseband audio signal 23 based on the analog demodulation stable signal 35. That is, based on the analog demodulation stable signal 35, the controller 38
During the timing when the analog baseband video signal 24 is stable and there is no sense of incongruity between the analog baseband video signal 24 and the analog baseband audio signal 23, the mute of the audio mute unit 13 is turned on. Turn off.

[0004] For example, when the controller 38 determines that the HV synchronization signal of the demodulated analog baseband video signal 24 after tuning is stabilized, the mute of the audio mute unit 13 is turned off. On the other hand, in the case of a scrambled analog broadcast signal, if the controller 38 determines that demodulation and descrambling of video have been performed, and if the audio is PCM data, the controller 38 determines that it has stabilized from the numerical value of the error rate, the audio mute unit 13 Turn mute off.

[0005] Even when the channel is not selected, the reception state of the analog broadcast signal, C / N (carrier /
The deterioration of the noise) ratio is detected, and the mute on / off control of the audio mute unit 13 is performed.

[0006]

However, in the configuration of FIG. 2 as described above, only an analog broadcast signal can be received. However, a configuration for receiving a digital broadcast signal is added to the configuration of FIG. In the case where the receiver can receive the digital broadcast signal and the analog broadcast signal in common, the selection from the digital broadcast signal channel to the digital broadcast signal channel or the change from the analog broadcast signal channel to the analog broadcast signal channel is performed. In channel selection, the audio mute timing can be controlled accurately,
When selecting a channel from a digital broadcast signal channel to an analog broadcast signal channel, or vice versa, selecting an analog broadcast signal channel to a digital broadcast signal channel, the analog video signal is stable against audio noise generated at the time of channel selection. Quickly determine whether the analog demodulated stable signal that indicates that the signal has been output or the digital demodulated stable signal that indicates that the digital video signal is stable is valid, and control the on / off of the audio mute unit at the appropriate timing Therefore, it is impossible to prevent the viewer from feeling uncomfortable. In order to solve the problem, it is necessary to know whether the selected new channel is a digital broadcast signal or an analog broadcast signal at the same time as the selected channel.

Therefore, an object of the present invention is to provide an accurate timing even when selecting a channel from a digital broadcast signal channel to an analog broadcast signal channel or vice versa. The object of the present invention is to provide an audio mute device capable of controlling on / off of an audio mute device so as to prevent a viewer from feeling uncomfortable.

[0008]

An audio mute apparatus according to the present invention is an audio mute apparatus incorporated in a receiver capable of receiving a digital broadcast signal and an analog broadcast signal in common, and is transmitted from a center. A downlink data demodulator that outputs a downlink data signal including a channel number of each receivable channel by demodulating the downlink data modulation signal and broadcast form information indicating whether the channel is an analog broadcast signal channel or a digital broadcast signal channel, A channel memory for storing the channel number of each receivable channel and broadcast format information in the downlink data signal output from the downlink data demodulator, and a channel number and channel memory indicated by the input channel data signal Compare the channel number of each channel stored in Identifies whether the channel is an analog broadcast signal or a digital broadcast signal, and, in accordance with the identified broadcast signal, in the case of an analog broadcast signal, indicates that the demodulated analog video signal is stable. In addition to determining that the broadcast signal is stable, in the case of a digital broadcast signal, it is determined that the digital broadcast signal is stable from a digital demodulated decoded stable signal that indicates that the demodulated and decoded digital video signal is stable, and that the analog broadcast signal is stable. A channel comparator that outputs an audio mute timing switching signal with a delay time set for an analog broadcast signal in the case of an analog broadcast signal, and outputs an audio mute timing switching signal with a delay time set for a digital broadcast signal in the case of a digital broadcast signal. And the audio signal output from the channel comparator. And a audio mute unit for performing on-off control of an audio muting accordance chromatography preparative timing switching signal.

In this audio mute device, a signal transmitted from the center, for example, FS in the current analog CATV
From the downlink data signal obtained by demodulating the downlink data modulation signal, which is K start-stop synchronous serial data, with the downlink data demodulator, whether each channel is an analog broadcast signal channel or a digital broadcast signal channel is compared with each channel number. The indicated broadcast form information is stored in the channel memory by bit setting.

[0010] The channel comparator compares the channel number indicated by the input channel selection channel data signal with the channel number of each channel stored in the channel memory, and determines whether the newly selected channel is an analog broadcast signal. A digital broadcast signal or a digital broadcast signal is identified from the bit data in the channel memory. At the same time, in the case of an analog broadcast signal, an analog demodulated stable signal indicating that the demodulated analog video signal is stable is used in accordance with the identified broadcast signal. The digital broadcast signal is determined to be stable, and in the case of a digital broadcast signal, the digital broadcast signal is determined to be stable from the digital demodulated decoded stable signal indicating that the demodulated digital video signal has been stabilized, and the analog broadcast signal The delay time for analog broadcast signals. And it outputs the audio mute timing switching signal.

That is, the analog mute signal is supplied to the audio mute device with an analog mute timing signal having a delay for analog broadcast signals and a digital mute signal for digital broadcast signals. Then, the audio mute unit has a delay corresponding to the digital broadcast signal and the analog broadcast signal, respectively.
On / off control of the audio mute is performed. With the above-described configuration, in a receiver that can receive a digital broadcast signal and an analog broadcast signal in common, a channel is selected from a digital broadcast signal channel to an analog broadcast signal channel, or vice versa. Even in the case of tuning to,
As in the case of selecting a channel from a digital broadcast signal channel to a digital broadcast signal channel or selecting a channel from an analog broadcast signal channel to an analog broadcast signal channel, the generated audio noise is muted at an appropriate timing, and the Pleasure can be avoided.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An audio mute device according to an embodiment of the present invention will be described below with reference to FIG.
In FIG. 1, reference numeral 1 denotes, for example, a channel number of each receivable channel by demodulating a downlink data modulation signal 16 transmitted from the center on a data dedicated channel, and indicates whether the channel is an analog broadcast signal channel or a digital broadcast signal channel. This is a downlink data demodulator that outputs a downlink data signal 17 including broadcast form information.

Reference numeral 2 denotes channel data 1 comprising a channel number of each receivable channel in the downlink data signal 16 output from the downlink data demodulator 1 and broadcast format information.
8 is a channel memory for storing the channel number 8. 3 compares the selected channel number indicated by the input selected channel data signal 19 with the channel number of each channel in the channel data 18 stored in the channel memory 2 and determines whether the newly selected channel is analog. At the same time as identifying whether the signal is a broadcast signal or a digital broadcast signal, an analog broadcast signal is output from an analog demodulation stable signal 35 indicating that the demodulated analog baseband video signal 24 has become stable in accordance with the identified broadcast signal. It is determined that the signal is stable, and in the case of a digital broadcast signal, the digital broadcast signal is stabilized from the digital demodulated and decoded stable signal 36 indicating that the demodulated and decoded MPEG baseband video signal (digital baseband video signal) 28 is stable. Judgment has been made and analog broadcasting In the case of a signal, an audio mute timing switching signal 30 with a delay time set for an analog broadcast signal is output, and in the case of a digital broadcast signal, an audio mute timing switch signal 30 with a delay time set for a digital broadcast signal is output. Channel comparator.

Reference numeral 13 denotes an audio mute device for performing on / off control of audio mute according to an audio mute timing switching signal 30 output from the channel comparator 3.
The audio mute unit 40 is configured by the above configuration and the data audio data mute unit. Next, parts other than the audio mute device 40 in the receiver of FIG. 1 will be described. Reference numeral 4 denotes a tuning controller which receives a tuning channel data signal 19 and generates a channel tuning signal 20. Reference numeral 5 denotes a tuner for performing a channel selection operation in accordance with a channel selection signal 20 given from the channel selection controller 4, and receives an analog / digital broadcast RF signal 21 and outputs an analog / digital broadcast IF signal 22 corresponding to the selected channel. I do.

Reference numeral 6 denotes an analog / digital broadcast IF signal 22 input from the tuner 5 to output an analog baseband video signal 24 and an analog baseband audio signal 23, and an analog signal when the analog baseband video signal 24 is stabilized. This is an analog broadcast signal detection / demodulator that outputs a demodulation stable signal 35. Reference numeral 7 denotes a digital broadcast signal detection / demodulator that receives an analog / digital broadcast IF signal 22 from the tuner 5 and outputs an MPEG transport stream 25 and a stable signal 36a. Reference numeral 8 denotes an input of the MPEG transport stream 25 from the digital broadcast signal detector / demodulator 7 to output an MPEG video signal 26 and an MPE.
An MPEG video / audio decoder that outputs a G audio signal 27 and a stable signal 36b. 39 is a stable signal 36a, 36
b is a gate for generating a digital demodulation and decoding stable signal 36. The digital demodulation and decoding stable signal 36 is supplied to the channel comparator 3 and the digital audio data mute unit 12. The digital audio data mute unit 12 outputs a data audio data mute signal 37 and sends it to the MPEG video / audio decoder 8.

Reference numeral 9 denotes a signal from the MPEG video / audio decoder 8 to the MP
This is an NTSC encoder that receives an EG video signal 26 and outputs an MPEG baseband video signal 28. Reference numeral 10 denotes an MPEG audio signal 27 from the MPEG video / audio decoder 8.
And outputs a MPEG baseband audio signal 29. Reference numeral 11 denotes a video / audio output switching signal 31 output from the channel comparator 3, an analog baseband video signal 24 and an analog baseband audio signal 23 input from the analog broadcast signal detector / demodulator 6, and an MPEG signal from the NTSC encoder 9. The baseband video signal 28 is input and the D / A converter 10
An audio / video switch for inputting a baseband audio signal 29, and outputs an analog baseband audio signal 23 as a baseband audio signal 33 when a selected channel is an analog broadcast signal in accordance with a video / audio output switching signal 31. And the analog baseband video signal 2
4 is output as a baseband video signal 34, and when the selected channel is a digital broadcast signal, the
The baseband audio signal 29 is converted to the baseband audio signal 33.
And outputs the MPEG baseband video signal 28 as the baseband video signal 34.

Reference numeral 14 denotes a video mute timing device, and 15 denotes a video mute device controlled by a video mute signal 32 output from the video mute timing device 14, and mutes a baseband video signal 34. In a receiver capable of receiving the digital broadcast signal and the analog broadcast signal in common as described above, for example, in the case of the current analog CATV, for example, in the current analog CATV, the downlink is the start-stop synchronous serial data which is FSK-modulated. The data modulation signal 16 is the downlink data demodulator 1
Is demodulated. Then, based on the downlink data signal 17 demodulated by the downlink data demodulator 1, whether each channel is an analog broadcast signal channel or a digital broadcast signal channel is stored in the channel memory 2 by bit setting in comparison with each channel number. Is done.

The channel comparator 3 compares the channel number indicated by the selected channel data signal 19 input from the remote controller or the like to the receiver with the channel number stored in the channel memory 2 to newly select a channel. At the same time as discriminating whether the channel is an analog broadcast signal or a digital broadcast signal from the bit data in the channel memory 2, the analog broadcast signal is input to the audio-video switch 11 in accordance with the identified broadcast signal. The audio / video switching unit 11 is controlled so that the baseband audio signal 23 is supplied to the audio mute unit 13 as the baseband audio signal 33. Further, it is determined that the video signal is stable from the analog demodulation stable signal 35 indicating that the demodulated analog baseband video signal 24 has become stable, and the audio mute timing switching signal 30 having a delay time for analog is converted to an audio mute. Give to 13. As a result, the audio mute unit 13 performs on / off control of the audio mute with a delay time according to the audio mute timing switching signal 30.

On the other hand, in the case of a digital broadcast signal, the audio / video switching unit 11 supplies the MPEG baseband audio signal 29 input to the audio / video switching unit 11 to the audio mute unit 13 as a baseband audio signal 33. Control. Also, the demodulated and decoded MPEG video signal 26
It is determined from the digital demodulation decode stabilization signal 36 indicating that the video signal has stabilized, and the audio mute timing switching signal 30 having a digital delay time is given to the audio mute unit 13. As a result, the audio mute unit 13 performs on / off control of the audio mute with a delay time according to the audio mute timing switching signal 30.

Here, the reason why audio mute is required when receiving an analog broadcast signal and a digital broadcast signal will be briefly described. For example, when the receiver tunes to a digitally transmitted channel, MPEG audio is decoded and output as an analog audio signal via a DA converter. On the other hand, when the receiver tunes to a channel that is being transmitted in analog, the analog audio signal is output through the same analog demodulation circuit as the TV. In each case, the audio is muted to delay the timing appropriately so that the output timing of the video signal (the time when the picture appears on the TV screen) and the audio do not become unnatural.

This timing differs between a mute delay applied when an analog broadcast channel is received and a mute delay applied when a digital broadcast channel is received. Therefore, the mode of channel selection is as follows. 1. Analog channel to analog channel 2. Digital channels to digital channels 3. Analog to digital channels There are four cases, from digital channels to analog channels.

In the case of a digital broadcast channel,
The CPU determines whether or not 64QAM reception and error correction are stable and whether or not MPEG audio has been decoded, and determines a lock signal indicating whether or not they can be normally decoded, and mutes the signal.
Therefore, it is only when these signals are stabilized that the digital channel is confirmed. In an analog broadcast channel, since there is no judgment signal, an appropriate fixed time mute is applied.

Therefore, in the present invention, the above-described unstable data is transmitted by using the downlink data from the center to the terminal and transmitting the broadcast form information indicating whether each channel is an analog broadcast channel or a digital broadcast channel in advance. Regardless of the judgment, the receiver can quickly recognize whether it is an analog broadcast channel or a digital broadcast channel, and the best mute corresponding to each can be applied.

Here, there is no problem in switching from analog to analog and digital to digital because the same demodulator is used because of the change from the same modulated wave to the same modulated wave. However, since the demodulator is completely different from digital to analog or from analog to digital, the method of determining whether demodulation is stable is completely different. For example, in the case of analog, it is determined by AGC, AFC, H-SYNC, etc., and in digital, 64QAM, error correction, MPE
The determination is made based on the error signal output and the lock signal of each G decode.

Since these signals from the tuner 5 are input to both the analog demodulator and the digital demodulator (there may be an analog / digital input switching circuit and control thereof). For example, when an analog signal is input, the analog demodulator operates normally, but the digital demodulator operates randomly. Also, at that time, the digital demodulator takes time to distinguish it from the initial unstable state when the power is turned on or when the channel is selected.

According to this embodiment, even when a channel is selected from a digital broadcast signal channel to an analog broadcast signal channel or vice versa, a channel is selected from an analog broadcast signal channel to a digital broadcast signal channel.
As in the case of selecting a channel from a digital broadcast signal channel to a digital broadcast signal channel or selecting a channel from an analog broadcast signal channel to an analog broadcast signal channel, the generated audio noise is muted at an appropriate timing, and the Pleasure can be avoided.

It is to be noted that downlink data from the center may be transmitted not only through a dedicated data channel but also by being superimposed within the band of a digital broadcast signal.

[0028]

As described above, according to the audio mute device of the present invention, in a receiver capable of receiving a digital broadcast signal and an analog broadcast signal in common, a channel is tuned from a digital broadcast signal channel to an analog broadcast signal channel. In the case of selecting a channel from an analog broadcast signal channel to a digital broadcast signal channel, or vice versa, selecting a channel from a digital broadcast signal channel to a digital broadcast signal channel or selecting a channel from an analog broadcast signal channel to an analog broadcast signal channel. As in the case of the station, the generated audio noise can be muted at an appropriate timing so that the viewer is not discomforted.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an audio mute device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional audio mute device.

[Explanation of symbols]

 Reference Signs List 1 downlink data demodulator 2 channel memory 3 channel comparator 4 tuning controller 5 tuner 6 analog broadcast signal detection demodulator 7 digital broadcast signal detection demodulator 8 MPEG video / audio decoder 9 NTSC encoder 10 D / A converter 11 video / audio Switch 12 Digital audio data mute unit 13 Audio mute unit 14 Video mute timing unit 15 Video mute unit 16 Downlink data modulation signal 17 Downlink data signal 18 Channel data 19 Channel selection channel data signal 20 Channel selection signal 21 Analog / digital broadcast RF Signal 22 analog / digital broadcasting IF signal 23 analog baseband audio signal 24 analog baseband video signal 25 MPEG transport stream 26 MPEG video signal 27 MPEG audio signal 28 MPEG baseband video signal 29 MPEG baseband audio signal 30 audio mute timing switching signal 31 video / audio output switching signal 32 video mute signal 33 baseband audio signal 34 baseband video signal 35 analog demodulation stable signal 36 digital demodulation decode stable signal 37 Digital audio data mute signal 38 Controller

Claims (1)

[Claims] An audio mute device incorporated in a receiver capable of receiving a digital broadcast signal and an analog broadcast signal in common, wherein each audio mute device can demodulate and receive a downlink data modulation signal transmitted from a center. A downlink data demodulator that outputs a downlink data signal including a channel number of a channel and broadcast format information indicating whether the channel is an analog broadcast signal channel or a digital broadcast signal channel; and the downlink data output from the downlink data demodulator. A channel memory for storing a channel number of each receivable channel in the signal and broadcast form information; a channel number indicated by an input channel data signal and a channel of each channel stored in the channel memory Compared to the number, the newly selected channel is analog broadcasting At the same time as identifying whether the signal is a digital broadcast signal or a digital broadcast signal, and in accordance with the identified broadcast signal, in the case of an analog broadcast signal, the analog broadcast signal stabilizes from the analog demodulated stable signal that indicates that the demodulated analog video signal has been stabilized. In addition to the determination, in the case of a digital broadcast signal, it is determined that the digital broadcast signal is stable from the digital demodulated decoded stable signal which indicates that the demodulated and decoded digital video signal is stable, and in the case of an analog broadcast signal, A channel comparator that outputs an audio mute timing switching signal in which a delay time is set, and in the case of a digital broadcasting signal, outputs an audio mute timing switching signal in which a delay time for a digital broadcasting signal is set, and the channel comparator According to the audio mute timing switching signal output from the And a sound mute device for performing on / off control of the sound mute.