JP4418582B2 - Receiver for radio broadcast programs transmitted in analog and digital - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, there are equivalent radio broadcast programs that are transmitted in analog and digital at different frequencies with respect to radio broadcast programs that are transmitted digitally, and the radio broadcast programs that are transmitted digitally are received in frames. To a receiver for radio broadcast programs transmitted in analog and digital form.
[0002]
[Prior art]
From European Patent Application Publication No. EP 086 517 5 A2, it is already known that there are receivers for radio broadcast programs that are transmitted in analog and digital form, in this case because of the very high frequencies and DAB (Digital Audio Broadcasting) For this purpose, one receiver is used separately. With this configuration, when one receiving unit is currently used to receive a radio broadcast program, the other receiving unit checks the equivalent radio broadcast program for its signal quality at that time and is currently aligned. When the signal quality of a radio broadcast program is reduced, it can be switched to the equivalent radio broadcast program. Such an equivalent radio broadcast program is the same radio broadcast program, but instead of being transmitted digitally, now it is transmitted in analog or vice versa and / or transmitted at another frequency Or a radio broadcast program, information and / or music corresponding to the radio broadcast program currently being matched. Accordingly, such a receiver has two receivers that operate in parallel to receive radio broadcast programs transmitted in analog and digital form.
[0003]
[Problems to be solved by the invention]
The problem of the present invention is that only one receiver is used to receive analog and digitally transmitted radio broadcast programs in a receiver of the type described at the beginning, and is currently aligned in the receiving time slot. The configuration is such that the quality of an equivalent radio broadcast program is inspected with respect to the radio broadcast program being recorded.
[0004]
[Means for Solving the Problems]
According to the present invention, the object is to provide a signal parameter representing the signal quality of at least one of an analog radio broadcast signal and a digital radio broadcast signal in an equivalent radio broadcast program when a radio broadcast program transmitted in digital or analog is received. Is measured at a predetermined time period, and a plurality of signal parameters representing reception qualities of the radio broadcast signal transmitted digitally and the radio broadcast signal transmitted analog are weighted differently and added to each other. the sum of a plurality of signal parameters is compared with the first threshold value, a sum of the plurality of signal parameters to an analog radio broadcast signal is compared with a second threshold value, the sum of said plurality of signal parameters of the digital radio broadcast signal If it is greater than the first threshold, it is transmitted digitally. Receiving radio broadcast program continues to be, or digital in switched to radio broadcast programs to be transmitted is smaller sum of said plurality of signal parameters of the digital radio broadcast signal than the first threshold value, the second is switched to the equivalent of analog transmission radio broadcast programs with the sum of the plurality of signal parameters is greater than the threshold value, if the sum of the plurality of signal parameters of the radio broadcast signal in a radio broadcast program is not greater than the second threshold it is solved by represented to be unreceivable.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Thus, according to the advantages of the receiver according to the invention for radio broadcast programs transmitted in analog and digital, there is only one receiver for receiving radio broadcast programs transmitted in analog and digital. However, the quality of the radio broadcast program equivalent to the currently set radio broadcast program is checked in the receiving time slot. Such time slots are configured to be so short that such a test cannot be heard by the user.
[0006]
Components are saved because only one receiver is used. As a result, the receiver becomes smaller and a simple structure is realized, which is particularly advantageous for incorporation in automobiles. Moreover, the cost of the receiver can be reduced if only a few components are used. Therefore, it is possible to provide a service at a low cost to the user so that the operation of the receiver for receiving a high-quality radio broadcast program is remarkably facilitated.
[0007]
The arrangements described in the dependent claims enable advantageous embodiments of the receivers described in the independent claims.
[0008]
It is particularly advantageous that only one antenna and / or high-frequency receiver and / or processor are required for the reception and processing of radio broadcast signals sent out in analog and digital transmission systems. . This significantly reduces the cost and size of the receiver. This is because only one component is used for processing analog and digital radio broadcast signals.
[0009]
Advantageously, in receiving a digitally transmitted radio broadcast signal, a section that does not contain information about the radio broadcast program currently aligned in one frame is used, within which the equivalent analog radio broadcast program and / or Digital radio broadcast programs are inspected for their signal quality. In this way, it is possible to prevent an audible effect from being caused by the examination, and as a result, the user will not be confused by such a measurement.
[0010]
According to one embodiment of the invention, a period of at least one frame is used to perform signal quality measurements of equivalent analog radio broadcast programs and / or digital radio broadcast programs. This has the advantage that an audible effect is hardly caused by the loss of one frame. This is because the audio information of a radio broadcast program is divided into a number of frames, and the loss of one frame can be compensated by using an error correction method.
[0011]
Moreover, it is advantageous if data having a list of equivalent radio broadcast programs is included in the radio broadcast program. This allows the receiver processor to easily set the frequency from the list in order to quickly check the signal quality of the equivalent radio broadcast program.
[0012]
More advantageously, if the analog transmission radio broadcast program has a low audio level, the receiver switches from the analog transmission radio broadcast program to the digital transmission radio broadcast program.
[0013]
It is also advantageous to measure the signal field strength of an equivalent radio broadcast program as a signal parameter for the purpose of determining whether switching to an equivalent radio broadcast program is possible. The signal field strength is a compelling signal parameter that can be easily measured.
[0014]
For digitally transmitted radio broadcast programs, it is advantageous to measure the baseband energy, the result of the synchronization attempt, the signal field strength of the adjacent channel, and the bit error rate as separate signal parameters. The purpose is to obtain an image with a tabular output regarding the quality of the equivalent radio broadcast program based on these various signal parameters.
[0015]
Further advantageous for analog transmission radio broadcast programs is signal to noise ratio, frequency deviation, multipath propagation estimation, adjacent channel signal field strength, pilot tone detection, frequency shift, and digital carrier such as RDS ( Radio Data Signal) is measured as a signal parameter, and its purpose is to determine whether or not switching to an equivalent analog transmission radio broadcast program is possible.
[0016]
According to one embodiment of the present invention, various signal parameters measured for the equivalent radio broadcast program are weighted and added to determine whether switching to the equivalent radio broadcast program is possible. And then compared to a threshold. As a result, it is possible to avoid making an erroneous impression on the signal quality of an equivalent radio broadcast program by measuring only one signal parameter.
[0017]
Advantageously, the above threshold values are loaded from memory, in which case they are pre-given and / or they can be calculated by the receiver's processor or respond to the situation. In order to make it possible to respond to, for example, generally poor reception conditions, at least recalculation is performed.
[0018]
Further advantageously, the signal parameters of the equivalent digital radio broadcast program and / or the analog radio broadcast program are measured in a short period of time which is determined in advance so that no audible effect occurs when receiving the analog transmission radio broadcast program.
[0019]
Next, the present invention will be described in detail based on examples with reference to the drawings.
[0020]
【Example】
Digital radio broadcast programs transmitted on the ground are broadcast at the same time as existing analog broadcast radio broadcast programs. By introducing this program, radio receivers such as analog broadcast radio broadcast programs are also digitally transmitted. There is a need for an in-vehicle wireless receiver that can also receive radio broadcast programs. An important reference measure for such a receiver is to have as little price as possible and as little volume structure as possible.
[0021]
Since analog broadcast radio programs and digitally transmitted radio broadcast programs exist in parallel with each other and are transmitted with various qualities at a specific location, such a receiver is configured as follows. Is needed. In other words, when the signal quality of the current radio broadcast program falls below a threshold, the equivalent radio broadcast program is inspected during reception for the purpose of automatically switching to such an equivalent radio broadcast program. Must be configured as follows. What is important here is to make the receiver user inaudible and not aware of the effects of the above measurements. Also, pay attention to the various signal parameters of the radio broadcast program for the purpose of creating a comprehensive image of the reception quality of the radio broadcast program, or at least to ensure that proper results are obtained by measuring the signal parameters. Must.
[0022]
In the case of DAB (Digital Audio Broadcasting) which is particularly suitable for reception on the ground in a moving vehicle, there is currently no service area covering the whole, and all analog radio broadcast programs are transmitted. It is not broadcast by DAB. For this reason, when leaving the service area of a radio broadcast program broadcast by DAB, it is necessary to automatically switch to an equivalent radio broadcast program to remove from the driver the burden of manually searching for a new radio broadcast program. is there.
[0023]
The same applies to radio broadcast programs transmitted by other digital transmission schemes such as DVB (Digital Video Broadcasting), DRM (Digital Radio Mondial) or ATSC (Advanced Television Systems Commitee), or the like. This also applies to radio broadcast programs that are at least planned to transmit radio broadcast programs using such digital transmission schemes.
[0024]
According to the present invention, this object is achieved by a receiver for digital and analog transmitted radio broadcast programs for a short period of time, measuring the signal parameters of an equivalent radio broadcast program without causing an audible effect. It is solved by.
[0025]
FIG. 1 depicts a receiver according to the present invention. In this case, the antenna 1 is connected to the high frequency receiver 2. Digital and analog radio broadcast signals received by the antenna 1 are filtered and amplified by the high frequency receiver 2 and further converted to an intermediate frequency.
[0026]
The high frequency receiving unit 2 is connected to the processor 3 via the input / output side. The processor 3 receives the signal converted to the intermediate frequency by the high-frequency receiving unit 2, first digitizes and decodes the signal, performs digital DAB / ultra-high frequency signal processing, and then passes through the first data output side. To the audio processing unit 4 connected to the processor 3. The processor 3 sends data about which frequencies, that is, which radio broadcast programs are to be filtered and extracted from the spectrum, to the high frequency receiver 2. The audio processing unit 4 is connected to the speaker 5 via the first output side. Further, the processor 3 is connected to the display 13 via the second data output side.
[0027]
The voice processing unit 4 processes the digital data and prepares for an acoustic expression by the speaker 5. If the received data includes not only audio data but also data to be displayed by the display 13, the processor 3 processes the digital data and prepares for optical expression. In this case, the display 13 is a screen, but may be another projection technology.
[0028]
By using the antenna 1, both analog broadcast radio broadcast signals and digital radio broadcast signals are received. The radio broadcast signal transmitted in analog includes, for example, an ultrashort wave signal, which also has a digital carrier (RDS = Radio Data System). The ultra-short wave has the best signal quality among radio broadcast programs transmitted in analog. Nevertheless, it may be a medium wave or a short wave. Various data can be given to the RDS, for example, information on the frequency at which an equivalent radio broadcast program is transmitted.
[0029]
Here, equivalent radio broadcast programs represent the same radio broadcast program, which is transmitted at a different frequency and / or transmitted in a different transmission scheme, ie digital instead of analog or analog instead of digital. Is done. Furthermore, an equivalent radio broadcast program also refers to a program having the same contents as the currently set radio broadcast program. In this case, for example, one communication transmission station is replaced with another communication transmission station. Information on what type of information or music is transmitted in individual radio broadcast programs is included in the data transmitted together in digitally transmitted radio broadcast programs, even in the case of ultra-short waves RDS is used for this purpose.
[0030]
For radio broadcast programs that are digitally transmitted, for example, a transmission system DAB (Digital Audio Broadcasting) is performed. DAB has a complex frame structure, which allows other data such as multimedia data to be transmitted together with audio data. Furthermore, in the case of DAB, the signal to be transmitted is divided into a number of different frequencies in order to minimize the influence of frequency selective attenuation on the received signal. This is because by dividing the signal into different frequencies, only a small percentage of the transmitted signal is disturbed by frequency selective attenuation. In that case, such a fault can be corrected by an appropriate error identification and error correction scheme. Systems similar to DAB are DVB (Digital Video Broadcasting) and DRM (Digital Radio Mondial). These systems differ from DAB in particular in terms of transmission frequency, transmission rate and precise frame structure. However, these methods can also be applied to the apparatus according to the present invention. In contrast, ATSC has a signal only at one frequency.
[0031]
When a receiver according to the present invention receives a digitally transmitted radio broadcast program, the receiver performs a signal parameter measurement of a radio broadcast signal in an equivalent radio broadcast program for a short period of time. The time interval between each measurement can be quite long.
[0032]
If the signal parameter of the currently received radio broadcast program that is automatically supplied by the received data is greater than the first threshold, the digital radio broadcast program that is currently received will remain, and the currently received radio broadcast program If the signal parameter is below the first threshold, the digital broadcast program is switched to an equivalent digital transmission radio broadcast program. In this case, the radio broadcast program currently being received is transmitted digitally or analogly. A prerequisite for this is that the equivalent digital transmission radio broadcast program has a signal parameter greater than the first threshold.
[0033]
Thus, according to the present invention, the digital transmission radio broadcast program is given priority over the analog transmission radio broadcast program. This is because a digitally transmitted radio broadcast program has a clearly good signal-to-noise ratio, and has an attractive potential for multimedia applications. Can only be realized to a limited extent. In this case, when a change from the currently set radio broadcast program is required because the signal parameter has deteriorated, the same radio broadcast program at a different frequency is first searched, and at that time, the digital transmission radio broadcast program is first searched. However, the analog transmission radio broadcast program is searched next. If such a search is not successful, a radio broadcast program having an equivalent content is used, and at that time, the digital transmission radio broadcast program is first checked and then the analog transmission radio broadcast program is checked again.
[0034]
Even when the audio level of the combined analog transmission radio broadcast program is lowered, it is still switched to the digital transmission radio broadcast program, and as a result, the SN ratio is noticeably interrupted as an interruption of the ongoing program or as a faulty action. It will be limited to the limit.
[0035]
If the signal parameters of all equivalent digital transmission radio broadcast programs and the signal parameters of the currently receiving digital radio broadcast program are less than the first threshold, the equivalent analog transmission radio broadcast program is switched and this is done This is when the signal parameter of the analog transmission radio broadcast program is larger than the second threshold. If the signal parameter of the analog transmission radio broadcast program is smaller than the second threshold, it is displayed on the display 13 that reception is impossible.
[0036]
These thresholds are loaded from a memory connected to the processor 3, where the thresholds are determined in advance, and more particularly based on empirical research on the audio quality of the received radio broadcast program. In accordance with one embodiment of the invention, these thresholds are calculated by the processor 3 based on the loaded thresholds in order to respond to changes in reception conditions, and thus matching to those reception conditions is performed.
[0037]
As an alternative to this, the processor 3 may be configured to continuously recalculate the threshold based on the stored mathematical model and the current reception conditions.
[0038]
FIG. 2 shows a DAB frame. The DAB frame field 6 contains a synchronization signal and information on the frame structure. The field 7 of the DAB frame contains data related to the radio broadcast program A, the field 8 contains data related to the radio broadcast program B, and the field 9 contains data related to the radio broadcast program C. Currently, it is tailored to radio broadcast program B. For this reason, the radio broadcast program equivalent to the radio broadcast program B can be measured between the fields 7 and 9 in which unnecessary data is included in the currently set radio broadcast program. This also does not cause an effect of being heard by the user of the radio broadcast receiver. The reason is that the period of the fields 7 and 9 is insignificant anyway for the expression of the radio broadcast program B.
[0039]
As an alternative to this, measurement of the signal parameters of the equivalent radio broadcast program is performed over at least one entire frame. This also does not cause an effect that can be heard by the user. The reason is that in the case of DAB, the data is scrambled in time, that is, so-called time interleaving is performed. In this case, the audio information is divided into 16 DAB frames. If one of the frames is missing, that is, if 1/16 of the entire audio information is missing, it can be corrected by the error correction scheme already implemented.
[0040]
In the case of an ultra-short wave signal, even if the reception is interrupted for a very short time required for measuring the signal parameters of an equivalent radio broadcast program, there is no effect that the user of the receiver can hear. Such a short interruption is, for example, a period of 5 ms. In the case of ultrashort waves, the frequency list of equivalent radio broadcast programs is transmitted by RDS. Instead of transmitting a list of equivalent radio broadcast programs, it is also possible to transmit a list of all receivable radio broadcast programs, and the receiver can indicate what kind of radio broadcast program it is. Let them evaluate. In the case of DAB, a program format identifier is provided for this purpose, and RDS has a program information code. For radio broadcast programs that are analog and do not have a digital carrier, a list must be provided regarding what kind of music and information is transmitted in the radio broadcast program.
[0041]
In FIG. 3, an RDS group is depicted. The program identifier is shown in field 10, field 11 contains error detection information, and field 12 contains further information. The program information in field 10 can be used to determine what type of program information to be transmitted.
[0042]
The signal field strength is particularly suitable as a signal parameter suitable for the inspection of a radio broadcast signal of a radio broadcast program. This represents the strength with which the radio broadcast program is received. In the case of a digital radio broadcast signal, the baseband energy and / or the result of a synchronization attempt, or the signal field strength of an adjacent channel can be used as another signal parameter. The signal field strength of the adjacent channel represents crosstalk on the other transmission side, and it is not necessarily a radio broadcast transmission station. However, such a transmission side causes a significant interference with a certain radio broadcast program if the frequency interval is small, that is, the signal quality of the radio broadcast program is seriously damaged.
[0043]
In the case of analog radio broadcast signals, other signal parameters include signal to noise ratio and / or frequency deviation of the analog transmission radio broadcast program indicated by the RDS or DAB signal, or multipath propagation for the radio broadcast program. Channel estimation representing how it is, and / or signal field strength of adjacent signals, and / or pilot tone detection, and / or digital carrier detection, which is preferably RDS, and / or frequency shift Detection. As an alternative to channel estimation, it is also advantageous to use a symmetric detector. If the symmetric detector detects asymmetry, the cause can be multipath propagation. Such a method requires much less computational effort than channel estimation. For example, the symmetric detector obtains a symmetric signal from the sum signal and difference signal of stereo transmission, and identifies whether or not it is asymmetric based on the symmetric signal.
[0044]
For the purpose of obtaining an image of the signal quality of a radio broadcast program, various signal parameters can be weighted according to importance, forming a sum and comparing it with a corresponding threshold. This is a first threshold value for a digital radio broadcast signal, and a second threshold value for an analog radio broadcast signal. Alternatively, majority voting can be performed by determining a plurality of signal parameters. The signal parameter evaluation result using the threshold value is notified, and the notification results are compared with each other, for example, logical combination is performed. In this case, the individual signal parameters can also be weighted to compare them with the same threshold.
[0045]
Rather than simply using a high-frequency receiver and a processor, only one of these components can be used for ultra-high frequency and DAB, and the other two can be provided. This can provide advantages in processing.
[Brief description of the drawings]
FIG. 1 shows a receiver according to the invention for radio broadcast signals transmitted in analog and digital form.
FIG. 2 is a diagram showing a DAB frame.
FIG. 3 is a diagram showing an RDS group.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Antenna 2 High frequency receiving part 3 Processor 4 Sound processing part 5 Speaker 13 Display

Claims (10)

For radio broadcast programs transmitted digitally, there are equivalent radio broadcast programs transmitted in analog and digital at different frequencies. Radio broadcast programs transmitted digitally are received in frames, and analog and digital In a format in which a receiver with only one receiver is used to receive a radio broadcast program transmitted in
In a receiver for radio broadcast programs transmitted in analog and digital,
When receiving a radio broadcast program transmitted in digital or analog, a signal parameter representing the signal quality of at least one of an analog radio broadcast signal and a digital radio broadcast signal in an equivalent radio broadcast program is measured at a predetermined time period,
A plurality of signal parameters representing the received signal quality of the radio broadcast signal transmitted in digital and the radio broadcast signal transmitted in analog are weighted and added differently, and the sum of the plurality of signal parameters related to the digital radio broadcast signal is obtained. Compared to a first threshold, and the sum of the plurality of signal parameters for the analog radio broadcast signal is compared to a second threshold;
If the sum of the plurality of signal parameters of the digital radio broadcast signal is larger than the first threshold value, the reception of the radio broadcast program transmitted digitally is continued or switched to the reception of the radio broadcast program transmitted digitally. ,
If the sum of the plurality of signal parameters of the digital radio broadcast signal is smaller than the first threshold, the digital radio broadcast signal is switched to an equivalent analog transmission radio broadcast program having the sum of the plurality of signal parameters greater than the second threshold;
If the sum of the plurality of signal parameters of the radio broadcast signal in a radio broadcast program is not greater than the second threshold value, characterized in that it is represented that is unreceivable,
Receiver for radio broadcast programs transmitted in analog and digital.   At least one of the antenna (1) and the high-frequency receiver (2) is used to receive the digital and analog broadcast signals, or the receiver processor (3) deciphers the received digital and analog radio broadcast signals. The receiver of claim 1, wherein the receiver is coded.   Upon reception of a digital radio broadcast signal of a radio broadcast program, an audible effect is obtained by performing measurement for a part of one frame period with respect to signal parameters of analog and digital radio broadcast signals in an equivalent radio broadcast program. The receiver of claim 1, which does not occur.   When receiving a digital radio broadcast signal of a radio broadcast program, the measurement is performed only for one frame period on the signal parameters of the analog and digital radio broadcast signals in the equivalent radio broadcast program, and no audible effect is generated. Item 1. The receiver according to Item 1.   The receiver according to claim 3 or 4, wherein data indicating at which frequency an equivalent radio broadcast program should be searched is included in the radio broadcast signal.   6. A receiver according to any one of the preceding claims, wherein the signal field strength is compared with a threshold value as a signal parameter. The receiver according to claim 1, wherein a signal field strength or baseband energy, a result of synchronization trial or a bit error rate or a signal field strength of an adjacent channel is used as the signal parameter in the case of a digital radio broadcast signal.   In the case of an analog radio broadcast signal, the signal parameter is the signal field strength, the signal-to-noise ratio, or the deviation from the actual frequency related to the digital radio broadcast program equivalent to the frequency indicated in the data or the estimation of multipath propagation or the adjacent channel. The receiver according to claim 1, wherein signal field strength or pilot tone detection or digital carrier wave detection such as RDS or frequency shift is used.   9. A receiver according to any preceding claim, wherein the first and second thresholds are loaded from memory or calculated by a processor.   When receiving an analog radio broadcast signal in a radio broadcast program, at least one of the signal parameters of the equivalent digital and analog radio broadcast program is measured for a predetermined duration and does not produce an audible effect. The receiver according to any one of claims 1 to 9.

Images