JP2004282422A - Capture processor and capture processing method of analog/digital mixture broadcasting receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To minimize the sense of incongruity given to a user even though an FM capture phenomenon occurs in switching digital broadcasting to analog broadcasting. <P>SOLUTION: The user can easily confirm whether broadcasted contents are changed by the FM capture phenomenon when the digital broadcasting is switched to the analog broadcasting by providing a comparator 15 for comparing the contents of the analog broadcasting of IBOC digital voice broadcasting with the contents of the digital broadcasting to monitor whether the both contents are the same, and a microcomputer 6 for controlling a change-over switch 12 so as to switch the digital broadcasting to the analog broadcasting when the receiving intensity of the digital broadcasting drops and confirming that the analog broadcasting has contents different from those of the digital broadcasting and controlling a displaying part 8 so as to display to the effect that the broadcast contents are different in switching the digital broadcasting to the analog broadcasting. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a capture processing apparatus and a capture processing method for an analog / digital mixed broadcast receiver, and more particularly to a digital broadcast receiver for IBOC (In-Band On-Channel) digital audio broadcast which is a terrestrial digital radio broadcast in the United States. This is suitable for use in an apparatus for dealing with the FM capture phenomenon at the time of switching between analog and analog broadcasting.
[0002]
[Prior art]
Compared to conventional analog radio broadcasting, digital radio broadcasting has higher sound quality (equivalent to CD for digital FM and analog FM for digital AM), various data services, and higher receivability (fading and multi-channel) than current analog broadcast waves. High-quality voice reception even under a path environment is expected. For this reason, digital radio broadcasting is being developed at a rapid pace.
[0003]
However, until the transition from analog radio broadcasting to digital radio broadcasting is completed, many broadcasting stations need intermediate measures to simultaneously transmit analog broadcasting and digital broadcasting in the same band where use is permitted. It is. As a system corresponding to such an intermediate measure, there is an IBOC digital audio broadcast scheduled to start its service in the United States from the fall of 2003.
[0004]
This IBOC digital audio broadcast is characterized by performing digital broadcast in the same frequency band as conventional analog broadcast. That is, as shown in FIG. 3, by adding a digital modulation wave to the sideband of the existing analog AM / FM wave, the current dial position is maintained (On-Band) in the current analog radio band (In-Band). Channel) digital broadcast is transmitted (for example, see Patent Document 1).
[0005]
The audio portions of the analog broadcast and the digital broadcast superimposed on the same frequency band have the same broadcast content. In practice, an analog broadcast is transmitted from a broadcast station with a delay of a predetermined time (5.4 seconds for FM and 3.5 seconds for AM) compared to a digital broadcast having the same contents. On the receiver side, a digital broadcast signal that arrives before an analog broadcast is temporarily stored in a storage device, delayed, and then reproduced.
[0006]
The IBOC receiver can perform seamless switching between analog and digital using such features. For example, when a high-quality digital broadcast is normally played, but when entering an area where digital broadcast reception is difficult, that is, when the digital broadcast reception intensity falls below a certain value, the digital broadcast is switched to an analog broadcast. Is automatically switched (for example, see Patent Document 2).
[0007]
[Patent Document 1]
JP-T-2002-510897 [Patent Document 2]
Japanese Unexamined Patent Publication No. 2001-520479
[Problems to be solved by the invention]
As described above, when the digital signal is played back, if the bit rate of the digital signal decreases due to some interference (such as the occurrence of adjacent interference or intrusion into a weak electric field area), the playback is automatically switched to the analog broadcast of the same content. Can be This makes it possible to continuously reproduce the same broadcast content even if the reception state of the digital broadcast deteriorates. However, when listening to the FM broadcast, a troublesome problem as described below may occur.
[0009]
Existing FM analog broadcasting has a problem specific to FM broadcasting called a capture phenomenon. That is, as shown in FIG. 4, in the FM broadcast, different broadcast stations 101 and 102 may transmit different broadcast contents using the same frequency band. In an area where radio waves from these different broadcasting stations 101 and 102 reach both (hereinafter, referred to as a capture generation area), different broadcast contents are received in the same frequency band. When there are multiple received radio waves, the feature of FM modulation is to switch to the one with higher sensitivity and play it back. Therefore, in the capture generation area, the sound of different broadcast contents may be switched every few seconds and heard. is there.
[0010]
Therefore, when the IBOC FM digital broadcast is reproduced, when the digital FM broadcast is switched from the digital broadcast to the analog broadcast due to some disturbance, if the above-described capture phenomenon occurs in the FM analog broadcast after the switch, A broadcast having a different content than the digital broadcast before the switching is reproduced. Therefore, there has been a problem that the user feels great discomfort.
[0011]
The present invention has been made to solve such a problem, and it is possible to minimize a sense of discomfort given to a user even when an FM capture phenomenon occurs when switching from digital broadcasting to analog broadcasting. The purpose is to.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problem, the present invention monitors whether or not both broadcasts have the same content by comparing the content of an analog broadcast reproduced in a receiver of a mixed analog / digital broadcast with the content of a digital broadcast. If it is detected that the two broadcasts do not have the same content, the user is notified that the broadcast content is different when switching from the digital broadcast to the analog broadcast.
[0013]
ADVANTAGE OF THE INVENTION According to this invention comprised as mentioned above, when switching from digital broadcasting to analog broadcasting, a user can easily confirm whether broadcast content changes by FM capture phenomenon.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration example of a mixed analog / digital broadcast (IBOC broadcast) receiver 100 to which the capture processing device according to the present embodiment is applied.
[0015]
As shown in FIG. 1, the IBOC broadcast receiver 100 of the present embodiment includes an antenna 1, a tuner 2, an analog broadcast decoder 3, a digital broadcast decoder 4, a storage device 5, a microcomputer (microcomputer) 6, an operation unit 7, and a display. The unit 8 is provided. The analog broadcast decoder 3 includes an analog demodulation circuit 11, a changeover switch 12, a D / A converter 13, an A / D converter 14, and a comparator 15. The digital broadcast decoder 4 includes a digital demodulation circuit 21.
[0016]
The antenna 1 receives an IBOC digital audio broadcast in which an analog broadcast and a digital broadcast are superimposed on the same frequency band. The tuner 2 processes the IBOC broadcast wave received by the antenna 1 and converts it into an intermediate frequency (IF) signal. The converted IF signal is input to analog broadcast decoder 3 and digital broadcast decoder 4.
[0017]
Inside the analog broadcast decoder 3, an analog demodulation circuit 11 demodulates an IF signal according to an analog demodulation method corresponding to an analog modulation method in a broadcasting station (not shown), and converts the resulting analog information to one input of a changeover switch 12. Output to the end.
[0018]
Further, inside the digital broadcast decoder 4, the digital demodulation circuit 21 demodulates an IF signal according to a digital demodulation method corresponding to a digital modulation method in a broadcasting station (not shown), and outputs digital information obtained as a result to the storage device 5. I do. This storage device 5 functions as a delay circuit for realizing time diversity. That is, the digital information once stored in the storage device 5 is supplied to the D / A converter 13 of the analog broadcast decoder 3 after being delayed for a certain time.
[0019]
The D / A converter 13 converts digital information received from the digital broadcast decoder 4 via the storage device 5 into analog information, and outputs the analog information to the other input terminal of the changeover switch 12. As described above, the analog broadcast portion of the IBOC digital audio broadcast is transmitted from the broadcast station with a predetermined time delay compared to the digital broadcast portion having the same content. Therefore, by delaying the digital information by a predetermined time on the receiver side, analog information of the same broadcast content is input to both input terminals of the changeover switch 12 at the same time.
[0020]
The change-over switch 12 is used to switch between analog information generated by demodulating an analog modulated wave of IBOC digital audio broadcasting and analog information generated by demodulating a digital modulated wave and D / A converting the demodulated wave. The output is switched to an audio processing circuit (not shown). The audio processing circuit performs predetermined processing on the analog information to convert the analog information into a PCM format analog audio signal, and amplifies and outputs the analog audio signal from a speaker (not shown).
[0021]
The analog information output from the analog demodulation circuit 11 is also input to the A / D converter 14. The A / D converter 14 converts the input analog information into digital information by sampling it at a predetermined sampling frequency, and outputs the result to one input terminal of the comparator 15. The digital information delayed by a predetermined time in the storage device 5 is also input to the other input terminal of the comparator 15.
[0022]
The comparator 15 compares the broadcast content of the digital modulation wave input from the storage device 5 with the broadcast content of the analog modulation wave input from the A / D converter 14 to determine whether the contents of the two broadcasts are the same. To monitor. Specifically, digital information for a predetermined time stored in the storage device 5 by demodulating the digital modulation wave and analog modulation delayed by a predetermined delay (5.4 seconds of FM) from the digital modulation wave. The wave is demodulated and constantly compared with digital information for a predetermined time obtained by sampling. Thus, the comparator 15 constitutes the monitoring means of the present invention.
[0023]
FIG. 2 is a diagram for conceptually explaining the comparison operation by the comparator 15. FIG. 2A shows a case where the contents of the analog broadcast and the contents of the digital broadcast are the same (when the FM capture phenomenon does not occur), and FIG. 2B shows a case where the contents of the broadcast differ (the FM capture phenomenon occurs). Is shown). Here, for the sake of easy understanding as an image, both analog broadcasting and digital broadcasting are shown by analog waveforms, but the actual comparison is performed by digital information.
[0024]
As shown in FIG. 2A, in the case of FM broadcasting, analog broadcasting is transmitted and transmitted for 5.4 seconds from digital broadcasting having the same broadcasting content. At a certain timing, the comparator 15 compares the content 31 of the digital broadcast for a predetermined time with the content 32 of the analog broadcast for a predetermined time delayed by 5.4 seconds therefrom. If the analog broadcast and the digital broadcast have the same contents as shown in FIG. 2A, the comparator 15 outputs a coincidence signal.
[0025]
On the other hand, as shown in FIG. 2 (b), when the FM capture phenomenon occurs and the analog broadcast and the digital broadcast have different contents, the digital broadcast contents 31 for a predetermined time and 5.4. As a result of comparison with the analog broadcast content 33 for a predetermined time delayed by the second, the comparator 15 outputs a mismatch signal. The comparator 15 constantly performs such a comparison operation.
[0026]
Returning to FIG. 1, the operation unit 7 is for performing a reception channel switching operation, a volume operation, and other various operations, and is configured by, for example, a remote controller. The control data of the operation unit 7 is provided to the microcomputer 6 and is controlled by the microcomputer 6. For example, the channel switching information is supplied from the microcomputer 6 to the tuner 2, and the broadcast of the designated channel is selectively received.
[0027]
The display unit 8 displays information (for example, the name of a currently-received broadcasting station or a genre of a broadcasting station, the name of a currently-viewed song or artist, or the name of a genre, etc.) indicated by the accompanying data of the main broadcast and other various information. To display. The control data for the display unit 8 is controlled by the microcomputer 6 and is output from the microcomputer 6.
[0028]
The microcomputer 6 controls the entire IBOC broadcast receiver 100. For example, the switch 12 is controlled based on a switching request signal output from the digital broadcast decoder 4 in accordance with the reception strength of the digital broadcast to switch between analog broadcast and digital broadcast.
[0029]
That is, the microcomputer 6 normally switches the changeover switch 12 to the digital broadcast decoder 4 so as to process and reproduce a high-quality digital broadcast. On the other hand, when the reception strength of the digital broadcast becomes lower than a predetermined value due to some kind of reception disturbance, the changeover switch 12 is automatically switched to the analog broadcast decoder 3 side. Thus, the microcomputer 6 constitutes the switching control means of the present invention.
[0030]
When switching from digital broadcasting to analog broadcasting, the microcomputer 6 refers to the comparison result by the comparator 15. When it is detected that the content of the analog broadcast and the content of the digital broadcast are not the same (when the mismatch signal is output from the comparator 15), the display unit 8 informs the display unit 8 that the broadcast content is switched to a different broadcast content. Display and notify the user. As described above, the microcomputer 6 also constitutes the notification means of the present invention.
[0031]
Next, the operation of the IBOC broadcast receiver 100 according to the present embodiment configured as described above will be described. The IBOC broadcast wave received by the antenna 1 is converted into an IF signal by the tuner 2 and input to the analog broadcast decoder 3 and the digital broadcast decoder 4. In the analog broadcast decoder 3, the IF signal is demodulated by the analog demodulation circuit 11, and the generated analog information is input to the changeover switch 12 and the A / D converter 14. The analog information input to the A / D converter 14 is converted into digital information and input to the comparator 15.
[0032]
On the other hand, in the digital broadcast decoder 4, the IF signal is demodulated by the digital demodulation circuit 21, and the digital information generated thereby is stored in the storage device 5 and is delayed by a certain time. The delayed digital information is converted into analog information by the D / A converter 13 and input to the changeover switch 12, and is input to the comparator 15 as the digital information.
[0033]
In the comparator 15, the broadcast content of the digital modulation wave input from the storage device 5 and the broadcast content of the analog modulation wave input from the A / D converter 14 are constantly compared. While the monitoring by the comparator 15 is performed, the changeover switch 12 is switched to the digital broadcast decoder 4 so that high-quality digital broadcasting is normally reproduced. However, when the reception strength of the digital broadcast decreases due to some kind of reception disturbance, the digital broadcast decoder 4 outputs a switching request signal to the microcomputer 6.
[0034]
In response to the switching request signal, the microcomputer 6 refers to the comparison result of the comparator 15 and checks whether analog broadcasting and digital broadcasting have the same contents. Then, after confirming that both broadcasts have the same content, the changeover switch 12 is switched to the analog broadcast decoder 3 side. When it is confirmed that the two broadcasts are not the same, the changeover switch 12 is switched to the analog broadcast decoder 3 side, and the fact that the broadcast content is switched to a different broadcast content is displayed on the display unit 8 to notify the user.
[0035]
As described in detail above, according to the present embodiment, it is always monitored whether or not the digital broadcast of IBOC digital audio broadcast and the analog broadcast have the same content, and when switching from digital broadcast to analog broadcast, both are monitored. When it is confirmed that the content of the broadcast is different, the fact is displayed to notify the user. Thus, when switching from digital broadcasting to analog broadcasting, the user can easily check whether or not the broadcast content changes due to the FM capture phenomenon. Therefore, even if the broadcast content that is heard changes due to the occurrence of the FM capture phenomenon, it is possible to minimize the discomfort given to the user.
[0036]
In the above-described embodiment, an example in which the microcomputer 6 switches the digital broadcast to the analog broadcast when the microcomputer 6 confirms that the content of the digital broadcast is different from the content of the analog broadcast has been described. May not be switched to analog broadcasting. In this case, the digital broadcast having poor reception sensitivity is continuously reproduced, and during that time, there is no sound or noise. However, even in this case, by outputting a message to the display unit 8, the current situation can be conveyed to the user, and the discomfort given to the user can be minimized.
[0037]
When the content of the digital broadcast is different from the content of the analog broadcast, switching from the radio broadcast to another source reproduction (for example, CD (Compact Disc), MD (Mini Disc), DVD (Digital Versatile Disk), etc.) is performed. You may do it. Further, the user may arbitrarily select and set any of switching from digital radio broadcasting to analog radio broadcasting, switching to another source, or not switching.
[0038]
Further, in the above-described embodiment, the example in which the notification to the user is performed by the display on the display unit 8 has been described, but the notification may be output to the speaker by voice.
Further, in the above embodiment, IBOC was described as an example of analog / digital mixed broadcasting, but the present invention is not limited to this. That is, any analog / digital mixed broadcast in which a digitally modulated wave is added to the sideband of the analogly modulated wave, and which is configured to switch to the analog broadcast in an area where digital broadcast reception is difficult, Applicable.
[0039]
In addition, each of the above-described embodiments is merely an example of the embodiment for carrying out the present invention, and the technical scope of the present invention should not be interpreted in a limited manner. That is, the present invention can be embodied in various forms without departing from the spirit or main features thereof.
[0040]
【The invention's effect】
As described above, the present invention compares the contents of the analog broadcast and the contents of the digital broadcast of the mixed analog / digital broadcast and monitors whether or not the two contents are the same, and detects that the two contents are not the same. In this case, when the digital broadcast is switched to the analog broadcast, the user is notified that the broadcast content is different. Therefore, when the digital broadcast is switched to the analog broadcast, the broadcast that is heard due to the occurrence of the FM capture phenomenon. Even if the contents are changed, it is possible to minimize the discomfort given to the user.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration example of a mixed analog / digital broadcast (IBOC broadcast) receiver to which a capture processing device according to an embodiment is applied.
FIG. 2 is a diagram for conceptually explaining a comparison operation by the comparator of the embodiment.
FIG. 3 is a diagram showing an FM / AM spectrum of IBOC digital audio broadcasting.
FIG. 4 is a diagram for explaining an FM capture phenomenon.
[Explanation of symbols]
Reference Signs List 1 antenna 2 tuner 3 analog broadcast decoder 4 digital broadcast decoder 5 storage device 6 microcomputer 7 operation unit 8 display unit 11 analog demodulation circuit 12 changeover switch 13 D / A converter 14 A / D converter 15 comparator 21 digital demodulation circuit

Claims (4)

In a mixed analog / digital broadcast receiver that adds a digital modulation wave to the sideband of the analog modulation wave,
Switching control means for controlling to switch to the analog broadcast by the analog modulation wave and reproduce when the digital reception state deteriorates during the reproduction of the digital broadcast by the digital modulation wave,
Monitoring means for monitoring whether or not both broadcasts have the same content by comparing the broadcast content of the analog modulated wave and the broadcast content of the digital modulated wave,
When switching from the digital broadcast to the analog broadcast is performed by the switching control unit, the monitoring unit has detected that the broadcast content of the analog modulated wave and the broadcast content of the digital modulated wave are not the same. And a notifying means for notifying that the broadcast contents are different, in a case, the capture processing device of the analog / digital mixed broadcast receiver. The monitoring means is obtained by demodulating and sampling the digital information for a predetermined time obtained by demodulating the digital modulation wave and the analog modulation wave delayed by a predetermined delay from the digital modulation wave. 2. The capture processing device for a mixed analog / digital broadcast receiver according to claim 1, wherein digital information for a predetermined time is sequentially compared. The switching control unit performs switching from the digital broadcasting to the analog broadcasting when the monitoring unit detects that the broadcasting content of the analog modulation wave and the broadcasting content of the digital modulation wave are not the same. 2. The capture processing device for an analog / digital mixed broadcast receiver according to claim 1, wherein the capture processing is controlled so as not to occur. In a mixed analog / digital broadcast receiver that adds a digital modulation wave to the sideband of the analog modulation wave,
It is monitored whether or not both broadcasts have the same content by comparing the broadcast content of the analog modulated wave and the broadcast content of the digital modulated wave,
When a request for switching to analog broadcasting by the analog modulation wave is issued in response to the deterioration of the digital reception state during reproduction of the digital broadcasting by the digital modulation wave, the broadcast contents of the analog modulation wave and the digital modulation wave A method for notifying a user that the broadcast content is different, when it is detected that the broadcast content is not the same as the broadcast content of the analog / digital mixed broadcast receiver.

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