EP1113599A2 - Receiver for receiving analog and digital broadcast programmes, selecting the analog broadcast programme which corresponds to the digital programme when reception of the digital signal is no longer possible - Google Patents

Abstract

The receiver receives digitally transmitted programs in frames and measures parameters of analogue and/or digital broadcast signals of equivalent programs. If the signal parameters of digital signals are above a first threshold the receiver continues or changes over to receiving a digital program, otherwise it changes to an equivalent analogue program with parameters above a second threshold, otherwise it indicates that no reception is possible. The receiver receives digitally transmitted programs in frames. On receiving programs transmitted in digital or analogue form it measures signal parameters of respective analogue and/or digital broadcast signals of equivalent broadcast programs. If the signal parameters of digital signals remain above a first threshold the receiver continues or changes over to receiving a digitally transmitted program. If the parameter lies below the threshold the receiver changes to an equivalent analogue program with signal parameters above a second threshold. If no signals are above the second threshold the receiver indicates that no reception is possible.

Description

State of the art

The invention is based on a receiver for analog and digitally broadcast programs according to the genus of independent claim.

It is already known from published patent application EP 086 517 5 A2 known that receivers for analog and digitally transmitted Broadcast programs are available, each separately Receiver for FM (ultra short wave) and for DAB (digital Audio broadcasting) is used. This makes it possible that if a receiving part is currently receiving a Broadcasting program is used at this time the other Receiving part equivalent radio programs on their Checked signal quality to see if the Signal quality of the current broadcast program to switch to this equivalent radio program. This equivalent broadcast program is either the same Broadcasting program, now instead of digitally transmitting analogue transmitted or vice versa, and / or it will be on one transmit another frequency, or it's a Broadcasting program that contains information and / or music transmits the current broadcast program correspond. So this receiver has two in parallel working receiving parts on to analog and digital to receive broadcast radio programs.

Advantages of the invention

The receiver for analog and digital broadcast radio programs with the characteristics of In contrast, independent patent claims have the advantage that only one receiving part for receiving the analog and digitally broadcast programs are used and that in time slots during reception the quality of equivalents to the currently set broadcast program Broadcast programs is checked. These are time slots so short that this review is inaudible to one User is.

By using only one receiving part Components saved. This makes the receiver smaller and easier installation is possible, especially for installation in motor vehicles is advantageous. About that moreover, the use of fewer components leads to one cheaper price for the recipient. So it will be here enables a cost-effective service for the user who him using the receiver to broadcast programs with excellent quality received, very strong facilitated.

By those listed in the dependent claims Measures are advantageous training and Improvements in the independent claim specified recipient possible.

It is particularly advantageous that for the reception and the Processing of broadcast signals using an analog and have been sent using a digital transmission method, only one antenna and / or one radio frequency receiving part and / or a processor are necessary. This will cost and size of the recipient is significantly reduced because Components that only exist once for the Processing of analog and digital broadcast signals be used.

Advantageously, the sections of a frame when receiving digitally transmitted broadcast signals used in which no information for the current set radio program are included, then in analog and / or digital equivalent to these sections Check radio programs for their signal quality. This ensures that the check is not audible Effects leads so that the user through this measurement is not irritated.

In a development of the invention, at least the Duration of a frame used to measure the Signal quality of equivalent analog and / or digital To carry out broadcasting programs. This has the advantage that the loss of a frame leads to hardly audible effects, because the audio information of a broadcast program is on many Frame is distributed and the loss of a frame means Error correction method can be compensated.

In addition, it is advantageous that in the Broadcasting programs contain data that is a list of have equivalent radio programs. That’s it a processor of the receiver is possible in a simple manner, from this list set frequencies to in short Periods the signal quality of equivalents Check broadcasting programs.

It is also advantageous that the recipient of one analog broadcast program on a digital transmitted radio program switches if the analog broadcast radio program a low audio level having.

In addition, it is advantageous that as a signal parameter the signal field strength of equivalent radio programs is measured to decide whether to switch to a equivalent radio program is possible. The Signal field strength is a meaningful signal parameter, that can be measured easily.

Another advantage is that as additional signal parameters in the case of digitally transmitted radio programs Baseband energy, the results of one Attempting to synchronize, the signal field strength of Adjacent channels and the bit error rate are measured in order based on these different signal parameters meaningful picture about the quality of equivalents To win broadcasting programs.

In addition, it is advantageous that at analog broadcast radio programs a signal-to-noise ratio, a Frequency deviation, an estimate of the Multipath, a signal field strength of a Adjacent channel, a pilot tone detection, a frequency swing and an evaluation of a digital medium, preferably one RDS (Radio Data Signal), measured as signal parameters to make a decision on whether to equivalent analog broadcast program can be switched.

In a development of the invention it is provided that the different signal parameters for an equivalent Broadcast program can be measured, weighted and summed up and then compared to thresholds to decide whether to switch to this equivalent Broadcasting program is possible. This avoids that a wrong one by measuring only one signal parameter Impression of the signal quality of an equivalent Broadcasting program arises.

It is also advantageous that the threshold values either loaded from memory, then it are specified and / or are processed by the processor of the Recipient calculated or at least recalculated to a situation such as generally bad Reception conditions to respond.

Furthermore, it is advantageous that when receiving analog broadcast radio programs in predetermined short Intervals the signal parameters of equivalent digital and / or analog radio programs can be measured without that there is an audible effect.

drawing

Embodiments of the invention are in the drawing shown and in the following description explained. 1 shows an inventive Receiver for analog and digitally transmitted Broadcast signals, Figure 2 is a DAB frame and Figure 3 is a RDS group.

Description of the embodiments

Through the introduction of terrestrially transmitted digital Broadcasting programs that continue alongside that for the time being existing analog broadcast programs to be broadcast, there is a need for Radio receivers, especially for those in Motor vehicles that are both transmitted analog Broadcast programs as well as digitally transmitted Can receive radio programs. Important criteria for Such a recipient are the lowest possible price and the smallest possible construction volume.

Since analogue broadcast programs and also digital broadcast radio programs coexist and in certain places with different qualities transferred, it is necessary in such Receiver to provide equivalent broadcast programs to be checked during reception to an automatic Switch to such equivalent radio programs a reduction in the signal quality of the currently set Broadcast program below a threshold. The key here is that a user of the recipient perceives no audible effects from this measurement. Various signal parameters of To consider broadcast signals of a broadcast program in order to a comprehensive picture of the reception quality of the To provide broadcasting program or at least to insure whether the measurement of a signal parameter at a correct result.

At DAB (Digital Audio Broadcasting), which is especially for suitable for terrestrial reception in moving vehicles is currently not a nationwide one Coverage area, all are still transmitted analog Broadcast programs broadcast using DAB. Therefore at Leaving a supply area by means of DAB broadcast radio program an automatic Switching to an equivalent radio program necessary to the driver of a manual search for a new one To relieve broadcasting program.

The same applies to radio programs that use other digital transmission methods such as DVB (Digital Video Broadcasting), DRM (Digital Radio Mondial) or ATSC (Advanced Television Systems Committee) or at least it is planned to use radio programs to transmit this digital transmission method.

According to the invention this object is achieved in that a Receiver for digitally and analogue transmitted Broadcast programs in a short period of time a measurement of Signal parameters of equivalent radio programs performed without audible effects.

A receiver according to the invention is shown in FIG. An antenna 1 is with a radio frequency receiving part 2 connected. Digital and received by antenna 1 analog broadcast signals are from the High-frequency receiving part 2 filtered, amplified and in one Intermediate frequency implemented.

The high-frequency receiving part 2 is via an input / output connected to a processor 3. The processor 3 receives from the radio frequency receiving part 2 to one Intermediate frequency converted signals to them first digitize, decode, digital DAB / FM signal processing perform and then to one to the Processor 3 connected via a first data output Handover audio processing 4. The processor 3 sends the High frequency receiving part 2 data, which frequencies and so which radio programs from the spectrum are to be filtered out. The audio processing 4 is over one first output connected to a loudspeaker 5. The Processor 3 is connected to a via a second data output Display 13 connected.

The audio processing 4 prepares the digital data for the acoustic representation by means of the loudspeaker 5. The Processor 3 prepares the digital data for an optical one Presentation before if not only in the received data Audio data, but also data that is included are also to be represented by means of the display 13. The Display 13 is a screen, but also others Projection techniques are possible.

Antenna 1 transmits both analog and also receive digitally transmitted radio signals. To the Analog broadcast signals belong in particular VHF (ultra-short wave) signals, including a digital one Have carriers (RDS = Radio Data System). FM has from analog broadcast programs the best Signal quality. However, it is also medium wave and Shortwave possible. RDS can have different dates, so e.g. Information on frequencies on which equivalents Broadcast programs are transmitted.

Equivalent radio programs here either denote the same radio programs that are on different frequencies be transferred and / or by means of another Transmission process, i.e. digital instead of analog or analog instead of digital. The equivalent Broadcasting programs also refer to programs that a similar content to that currently set Show radio program. Here, e.g. on News broadcaster with another news broadcaster replaced. This program information, what kind of Information or music in a particular Broadcasting programs are broadcast at digital broadcast radio programs in co-transmitted data included and RDS is also used for FM.

For digitally broadcast radio programs in particular the DAB (digital audio Broadcasting). DAB exhibits a complex Frame structure that allows it, in addition to audio data further data, e.g. Multimedia data to be transmitted with. Furthermore, at DAB the signal to be transmitted is used on many different frequencies distributed to the effects of a frequency-selective attenuation to the received signal minimize. Because by distributing the signal different frequencies will only make up a small percentage of the transmitted signal by a frequency selective Damping disturbed. This disorder can then be corrected Error detection and correction procedures corrected become. Processes related to DAB are DVB (Digital Video Broadcasting) and DRM (Digital Radio Mondial). This Methods differ from DAB in particular in the Transmission frequencies, the transmission rate and the exact Frame structure. However, these procedures are also for the Device according to the invention can be used. ATSC points out Signals only at one frequency.

The receiver according to the invention receives a digital broadcast radio program, the receiver performs for short Periods of measurement of signal parameters from Broadcast signals from equivalent broadcast programs. The time intervals between measurements can be considerable be longer.

If now the signal parameters of the currently received Broadcasting program that automatically with the received data are available, are above a first threshold, then at the currently received digital Broadcast program remained, or it will be on equivalent digital broadcast program switched when the signal parameters of the current received radio program under this first Threshold value, be that currently received Broadcast radio program digital or analog. The prerequisite for this is that an equivalent digital broadcast radio program has signal parameters that are above the first threshold.

This is digitally transmitted according to the invention Broadcast programs always have priority over analogue broadcasts Broadcasting programs given as digitally transmitted Broadcast programs have a clearly better signal-to-noise ratio and still attractive opportunities for multimedia applications have that in analog transmitted Broadcast programs only to a very limited extent possible are. The procedure is such that if a change from the current broadcast program necessary due to deteriorating signal parameters is, initially according to the same radio program on a other frequency is sought, with digital and then analog broadcast programs are examined. If this search does not lead to success, then will Radio programs with equivalent content, again digital broadcast programs and then examined analog broadcast programs become.

When the audio level of a set analogue drops broadcast radio program is possibly on a digitally broadcast program switched over so that an interruption of a running program or a noticeable change in the signal-to-noise ratio as disruptive effects be minimized.

Now the signal parameters of all equivalents are digital broadcast radio programs and also the signal parameters of the digital broadcast program currently received at this first threshold, then it becomes equivalent transmitted analog radio program switched, if the signal parameters of this transmitted analog Broadcast program are above a second threshold. Are the signal parameters of this analog transmitted Broadcast program below the second threshold, then indicated by the display 13 that no reception possible is.

The threshold values are sent to the processor 3 connected memory loaded, these threshold values then be determined in advance based on experimental investigations regarding audio quality who receive radio programs. In a further education of Invention is provided that these threshold values from the Processor 3 based on the loaded threshold values are calculated to respond to changing reception conditions respond so that an adaptation to this Reception conditions exist.

Alternatively, it can be provided that the processor 3 based on stored mathematical models and the current reception conditions the threshold values continuously new be calculated.

A DAB frame is shown in FIG. In field 6 of the DAB framework are synchronization signals and information about included the frame structure. In box 7 of the DAB framework are Data for a radio program A contained in a field 8 Data for a radio program B and in a field 9 data for a radio program C. This is currently set Broadcasting program B. This can be during sections 7 and 9, which contain data currently set for the Broadcasting programs are not necessary to take measurements from that Broadcasting program B equivalent broadcasting programs be performed. This results in no audible Effects for the user of the radio receiver occur since the duration of sections 7 and 9 anyway for the Representation of the radio program B are irrelevant.

Alternatively it is provided that a measurement of Signal parameters of equivalent radio programs during at least one whole frame is carried out. This leads to no audible effects for the user, since the Data at DAB are scrambled in time, i.e. it is a so-called time interleaving. The Audio information distributed over sixteen DAB frames. Is missing now a frame of it, so a sixteenth of the Overall audio information, this can be done by already implemented error correction procedures are corrected.

FM signals are interrupted for a very short time of reception, which is used for the measurement of signal parameters of equivalent radio programs is necessary to none audible effects for the user of the receiver. Such a brief interruption has a duration of, for example 5 ms. In the case of FM, a list of the frequencies of equivalent broadcast programs. Instead of one List of equivalent radio programs is to be transmitted it is also possible to have a list of all broadcast programs, which can be received to transmit to the To let the recipient evaluate the nature of the respective radio programs are. At DAB there is one Program type identifier is provided and is at RDS Program information code. For radio programs that are transmitted analogously and which are not digital carriers must be specified in a list, which type of music and information on this radio program be broadcast.

An RDS group is shown in FIG. In box 10 is a program identification is given, in field 11 one Error detection and in field 12 are more information contain. The program information in field 10 can be used Determination of what type the transmitted Broadcasting program is.

As a signal parameter that is used to check the Broadcast signals from broadcast programs is suitable the signal field strength is particularly suitable. It indicates how strong a radio program is received. With digital Broadcast signals are the other signal parameters Baseband energy and / or results one Attempting to synchronize or the signal field strength of a Adjacent channel to use. The signal field strength of a Adjacent channel denotes another's crosstalk Transmitter that is not necessarily a radio broadcaster. Nevertheless, this transmitter can, if only a small one Has frequency distance to a radio program, a cause significant interference and thus the signal quality of the radio program decisively affect.

In the case of analog broadcast signals, there are more Signal parameters a signal-to-noise ratio and / or a deviation of the the frequency specified in the RDS or DAB signal is analog broadcast radio program or a channel estimate that indicates how the multipath propagation for this Broadcasting program presents itself and / or the Signal field strength of a neighboring signal and / or a Pilot tone detection and / or detection of a digital Carrier, which is preferably the RDS and / or the Determination of the frequency swing. As an alternative to channel estimation the use of a symmetry detector is an advantage. If the symmetry detector detects an asymmetry, this is attributable to multipath propagation. This method is considerably less computationally intensive than a channel estimate. The symmetry detector determines, for example, from one Sum and difference signal for stereo transmissions balanced signal and recognizes whether there is an asymmetry is present.

If one uses several such signal parameters to get one Image of the signal quality of a radio program can make the different signal parameters depending on Importance are weighted and you form a sum that is then compared with the corresponding threshold: Das is the first threshold for digital broadcast signals and the second for analog broadcast signals Threshold. Alternatively, by identifying multiple Majority of the signal parameters. The results of the evaluation of the signal parameters with Threshold values are signaled, and the Signaling results are then shared compared, for example with a logical link. The individual signal parameters can also be weighted to be using the same thresholds too to compare.

Instead of only one high frequency receiving part and one It is also possible to use only one processor to use these components for FM and DAB, and the other to have twice. This can have advantages in the Bring processing in.

Claims (12)

Receiver for analog and digitally transmitted Broadcasting programs, being for a digitally broadcast Broadcasting program also equivalent analog and digital broadcast programs on other frequencies, the receiver being the digitally transmitted Broadcast programs received in frames, thereby characterized in that the receiver when receiving the digital or analog broadcast programs in short Time periods signal parameters of analog and / or digital broadcast signals of equivalent Broadcast programs and that if the signal parameters of the digital radio signals above a first threshold lie in the receipt of a digitally transmitted Broadcasting program remains or upon receipt of a digitally broadcast radio program or that if the signal parameters of the digital broadcast signals under the first threshold, on an equivalent analog broadcast program switched, whose Signal parameters are above a second threshold or that if no signal parameters of broadcast signals of a Broadcast program are above the second threshold, then the receiver indicates that reception is not possible. Receiver according to claim 1, characterized in that an antenna (1) and / or a radio frequency receiving part (2) for receiving digital and analog radio signals serve and / or that a processor (3) of the receiver received digital and analog broadcast signals decoded. Receiver according to claim 1, characterized in that the receiver when receiving digital broadcast signals of a radio program during part of a Frame duration for the signal parameters of analog and digital radio signals of equivalent radio programs performs a measurement without the measurement becoming a leads audible effect. Receiver according to claim 1, characterized in that the receiver when receiving digital broadcast signals of a radio program during a framework for the Signal parameters of analog and digital broadcast signals equivalent radio programs perform a measurement without that the measurement leads to an audible effect. Receiver according to claim 3 or 4, characterized in that that the radio signals contain data that indicate on which frequencies equivalents Radio programs can be found. Receiver according to claim 5, characterized in that the receiver switches from an analog one Broadcasting program on a digitally broadcast equivalent Broadcasting program at a low audio level of the current Broadcasting program. Receiver according to one of the preceding claims, characterized in that the recipient as Signal parameters a signal field strength with a threshold compares. Receiver according to claim 7, characterized in that the receiver for digital broadcast signals as another Signal parameters the baseband energy and / or results a synchronization attempt, a bit error rate and / or a signal field strength of an adjacent channel is used. Receiver according to claim 7, characterized in that the receiver for analogue radio signals as another Signal parameters a signal-to-noise ratio and / or a deviation of the frequency specified in the data with the actual frequency for the equivalent digital broadcast radio program and / or an estimate of the Multipath propagation and / or a signal field strength of a Adjacent channel and / or a pilot tone detection and / or a Detection of a digital carrier, preferably an RDS, and / or a frequency swing is used. Receiver according to one of claims 7, 8 or 9, characterized characterized in that the recipient is different Signal parameters for digitally transmitted and analog broadcast radio signals weighted differently, summed and the sum for the digital broadcast signals with a first threshold and the sum for the analog Broadcast signals compared with a second threshold. Receiver according to one of the preceding claims, characterized in that the recipient the first and loads the second threshold value from a memory and / or by means of of the processor. Receiver according to one of the preceding claims, characterized in that when receiving analog Broadcast signals of a broadcast program in time segments predefined duration for the signal parameters of equivalents digital and / or analog radio programs a measurement performed without the measurement leading to audible effects.

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