DK175172B1 - Method of transmitting digital information in a radiophone signal - Google Patents

Abstract

The transmission system provides digital data corresp. to an alternative frequency or programme information code, identifying the other frequencies providing the same radio programme. This information is obtained by short-term switching of the receiver to each alternative frequency with evaluation of the reception quality to allow switching from the tuned frequency when an improved signal is obtained. Pref. the reception quality is evaluated using the signal distortion on its own or in addition to the reception field intensity, with the bit error rate of the radio data signal used as the criteria for the signal distortion.

Description

DK 175172 B1 i

The invention relates to a method as set out in the preamble of claim 1.

DE-C-34 32 848 discloses a method of the kind mentioned initially. It has been proposed to broadcast a series of alternate frequency lists for all transmitters in a transmitter group, each of these lists initially containing the operating frequency of the list associated with the transmitter in order to be able to transmit from the series of lists. select it at any time appropriate and for the received sender optimized list.

However, a safe reception of such a series of lists requires that the subsequent terming "head" of each list of operating frequencies for the transmitter associated with the list is received correctly. If this is not the case, e.g. due to interference due to multi-way reception, the alternate frequencies following the head of each list cannot be utilized on the receiving side, even when received correctly, as there is no proper connection to the operating frequency concerned.

Therefore, it has already been proposed (Blaupunkt-Werke GmbH, Hildesheim) to transmit 25 all alternative frequencies for a transmission chain, which can consist of several transmission groups (eg BR-north and BR-south), in the form of a matrix , with each transmitting alternate frequencies belonging to each array being grouped as ma-trix neighbors in the matrix. However, this so-called "matrix-30 method" has the disadvantage that, as a result of the grouping regulation, it is not possible to avoid neighbors who in reality do not have alternative frequencies in the meaning given above, so that on the receiving side DK 175172 B1 2 can occur similarly incorrect polls for such neighbors. Furthermore, setting up and modifying a matrix is extremely complicated, so re-coating a released transmit frequency cannot be possible because an existing matrix does not allow such a change.

In the technical document "Doc. Techn. No.

3244 "from the European Radiophone Union - hereinafter referred to as the" EBU Document "- specified 10 radio data systems (RDS), the transmission of additional information, such as the transmission of alternative frequencies (AF-Code), is used, in particular in the form of alternatives summarized in lists. frequencies as content in a 57 kHz auxiliary carrier modulated data stream.

15 This information is of interest, both in mobile reception (e.g. with car radios), e.g. when leaving a transmitter's radiating area, as in stationary systems, e.g. upon failure or disruption of a transmitter. By suitably designed receivers with layers, such lists can be stored, thereby reducing the time for tuning the transmitter at the optimum frequency in this list at all times (for example, according to optimum reception conditions).

The RDS data signal also contains, inter alia, a so-called program identification information (PI Code), whereby it is possible, directly by means of the AF Code and indirectly, by means of the PI Code to ascertain the alternative transmission frequencies at which the currently received program signal can also be received .

30 Utilization on the receiving side of the alternate transmit frequencies can be done in such a way that the receiver is briefly, successively ascertained at the alternate frequencies for each alternative frequency. Thereafter, the receiving field strengths for the alternative frequencies and for the currently received frequency are compared, after which the frequency is selected and used as a new receiving frequency which gives the greatest measured receiving field strength (this can of course also be the previously set reception frequency).

However, this raises the problem that there are cases where the measurement of the receiving field strength, especially at multi-way reception, does not give a reliable statement of the quality of the reception. In multi-way reception, the reception disturbances caused by signal reductions depend on the detour, on the immediate signal equipment (as determined by the program type, eg classical music or pop music) 15 and on mobile reception of the vehicle speed. A reception signal disturbed by multipath reception, despite a relatively high reception field strength between the signal reductions, may be subjectively felt extremely disturbed, whereas a reception signal alone disturbed by noise may feel substantially better.

As a result, the stated selection of the best possible reception of a selected program signal can cause the reception to be constantly damaged by multiple-way interference. This undesirable result cannot be substantially altered by the fact that e.g. by means of another tuner in the receiver for a longer measurement period, the alternate frequencies are tuned and the measured receive field strengths are integrated, since the received interfering reception signals also exhibit a greater average reception field strength than such received signals at such an integration. only disturbed by the rush.

4 GB 175172 B1 However, such interference can not only damage the program signal. Also the additional ones, e.g. information transmitted in the RDS data stream can be damaged by this, so that on the receiving side, under certain circumstances, it can either result in long waiting times until properly received RDS information is available, or for misinterpretation. This is especially negative in data whose repetition cycle in the data stream is relatively long.

10 A further problem of program signal quality is caused by the transmission network structure in some countries, in particular countries with overlapping transmission networks. Since the digital information sent by a main transmitter centrally, e.g. a list of alternate frequencies, which in some circumstances does not fit with the relays received by the main transmitter (eg, converters), must be filtered out by the relay receiver and replaced by the list applicable to the respective transmitter. This filtering out and 20 reinsertion are associated with an increased supply.

In addition, the quality of the program signal is degraded by the filtering.

The invention aims to provide an improvement in reception quality by methods of the kind set out initially.

This task is solved by the measures specified in claim 1.

The invention is based on the recognition that the reception quality can be improved by transmitting the alternative 30 frequencies so that they can be associated with the transmitter operating frequencies with greater certainty. This has the advantage that, if needed, the receiver can be tuned more quickly to an alternative frequency that provides better reception.

This is true even if the receiver has only a small storage capacity.

According to a further development of the invention, the reception quality can be improved by not receiving, or at least not exclusively, the reception field strength, but acoustic and / or program signal distortions. This has the advantage that alternative frequencies that are only "visible", namely due to a higher receive field strength, provide a better reception, but in fact feel worse by the user on the receiver side.

If, within the radiophone signal, 15 additional data transmitted, as in the case of RDS data signals, is in the form of digital information, the bit errors in the RDS data signal can be used as a measure of the program signal distortion. Namely, it has been found that the bit errors in the RDS data signal correspond relatively accurately to the program signal distortion, even if the program signal is transmitted in the baseband from 0 to 53 kHz, and the RDS signal on a 57 kHz carrier with a frequency swing of at least ± 1.2 kHz.

Because of this correlation, upon further development of the invention, it is possible to take advantage of the fact that interference resulting from multiple path sampling or interference causes sudden occurrence of bit errors in the RDS data signal, whereas interference resulting from noise causes uniform 30 distributions. bit errors. The degree of any interference can thereby be deduced from the block error rate, which can be ascertained completely independent of the data content.

6 DK 175172 B1

For optimum selection of the frequency that enables the best immediate reception, the receiver is accordingly tuned successively to the alternate frequencies and to the set 5 reception frequency in successive intervals. In a somewhat more comfortable receiver design, for optimum selection of the frequency that provides the best instant reception, a second tuner in the receiver that is successively tuned to the alternate frequencies and the tuned receive frequency of the first tuner is provided at intervals of eg. at least 2 sec.

During these - at the receiver construction with 2 tuners relatively long - tuning intervals 15, the bit errors for the total received RDS data signal are detected (which, in addition to the alternative frequencies, contain a wealth of additional information). In conjunction with this, they are utilized for each alternate frequency and for the instantaneous receive frequency, bit error distributions and block error rates as follows:

If all frequencies studied contain only sudden occurrences, or only uniformly distributed bit errors, which means that at all frequencies reception signal interference is caused by multipath reception, interference or noise, the corresponding block error rates are compared with each other, and the frequency that has the lowest block failure rate, selected as the optimal 30 receive frequency. The receiver's tuner or - in the case of a receiver with two tuners - the first tuner is then tuned to this selected frequency, provided that the already set reception frequency is not identical to the selected frequency.

In the case where the frequencies studied exhibit different interference, ie both bit-error from noise and bit error from multi-path reception, the frequencies which are essentially disturbed by noise and not by multi-path reception, are selected first. the frequencies with essentially uniformly distributed errors. To exclude 10 highly suspicious signals, only such frequencies can be preselected if RDS data signals do not exceed a maximum allowable block error rate.

Then, the preselected frequencies are compared with respect to their detected block error rate and the frequency with the minimum block error rate is selected as the optimal receive frequency.

Said selection of the optimum frequency can, at sufficiently long measurement intervals for each alternative transmitting frequency, be made without regard to the receiving field strength concerned. In particular, at smaller measurement intervals, the receiving field strength can also be included in the selection, as the weighting between receiving field strength on the one hand and signal distortions on the other can be determined empirically.

25 The alternative frequencies can be ascertained using the PI code or the AF code or during use and possibly combination - in case of ambiguities or incomplete transmission of both codes. The PI code identifies the frequencies at which the same program signal can be received. By comparing the PI Code with transmitter scanning, a clear association between the instantaneous reception frequency and its alternative frequencies can be obtained. This connection can be derived immediately from the AF code. If the AF code is not transmitted in the RDS data signal or if the AF code is faulty, the alternative frequencies can be derived from or supplemented by the PI code.

5 By means of the method according to the invention, it is possible for the first time, with a completely new idea for determining the optimum reception quality, to realize the 10 advantages of a continuous optimum reception in radio receivers by the introduction of the RDS system and the alternative frequencies contained therein. (both mobile and fixed radio receivers). By means of the RDS data signal, the problems with multi-way reception of the utility signal can thus surprisingly be significantly reduced.

It is provided by the method of the invention that in the series of individual lists contained in the digital information in the RDS data stream and containing the alternate frequencies associated with the individual transmitters in a transmitter chain, or alternatives for these transmitters. the corresponding frequency of operation contained in each list or corresponding to each list is transmitted not only at the beginning of the list but also before each alternative frequency in that list, so that each alternative frequency is "addressed" with the operating frequency.

Each list thus consists of a series of digital information blocks, each consisting of two information. One of these information in each block is (except for very specific exceptions), the operating frequency of the transmitter belonging to that list. If for some part of the list is transmitted or received incorrectly, the correctly received alternative frequencies, as a result of their pairing with the operating frequency, can be uniquely assigned to the corresponding transmitter, and therefore on the receiving side it is included in its list. Since it is unlikely that in the considered list there will always be a disturbance of the same information block, two or three successively disturbed lists may be stored for the same sender on the receiving side a complete list.

The stated pairing of each alternate frequency with the operating frequency of the transmitter of the list increases in comparison with the method of DE Patent No. 34 32 848 to the number of frequency information transmitted for each list to double, thereby increasing the cycle duration for each row of lists. , increases accordingly. Therefore, one would think that the reception probability and safety of such an extended cycle duration would rather be diminished than improved. In fact, for the above-mentioned matrix method, advantage is applied to the list method according to DE patent specification 34 32 20 848, a smaller cycle duration for a matrix against a number of individual lists, and from this a higher reception security can be deduced.

It should therefore be surprising to the art world that, despite the significant increase in the cycle duration in the range of lists performed according to the invention, the reception security is substantially greater than in the matrix method and the known list method. The unforeseeable reason for this surprising advantage lies in the fact that as a result of the described addressing of each alternative frequency with the operating frequency, even in extremely poor reception conditions, a secure association of the correctly received alternative frequencies is possible, which is not possible. in the case of the other methods, so that their shorter time cycle in such reception situations is of no use.

The invention is explained in more detail below with reference to three embodiments shown in the drawing, fig. 1 is a schematic representation of the array of alternate frequencies radiated by each transmitter in a transmitter chain according to a first embodiment of the invention; 2 is a circuit diagram of a receiver for use in connection with a method according to another embodiment of the invention; and FIG. 3 is a circuit diagram of a receiver for use in connection with a method according to a third embodiment of the invention.

In FIG. 1 is a schematic representation of a system of alternative lists transmitted as additional information from a radio transmitter. In the considered example, 20 is based on a radiophone signal in which a 57 kHz auxiliary carrier is inserted. The auxiliary carrier may contain an amplitude modulation that has a traffic characteristic for content. As a modulation or as a further modulation, the auxiliary carrier is imprinted with a data signal encoded in a particular manner which is of no interest here. This data signal is transmitted in accordance with all transmitters in a transmitter chain with the same program, e.g. of all transmitters in the transmitter chain "Bayern 3" in the Baye supply area 0 Rundfunk {abbreviated: BR). The assented transmitted data signal contains, inter alia, a list of alternative frequencies for all transmitters in the transmitter chain, in this case the list for transmitter # 1, the list for transmitter # 2, the list for transmitter # 3, until the list for transmitter # 29 for it case that the transmitter chain has 29 transmitters. Each list is adapted to that transmitter, and contains 5 alternate frequencies for that transmitter, that is, the frequencies of the transmitters in the transmitter's receiving range from which the same program can alternatively be received. Eg. Alternatively, the program "Bayern 3" in the area of Munich can be received from transmitter 10 "Wendelstein" or transmitter "Ismaning". If the receiver is set to the transmitter "Wendelstein", the receiver can with a reception deterioration, e.g. due to multipath reception, due to the knowledge of the "Ismaning" alternative, is briefly tuned to 15 reception from "Ismaning" and this transmitter's receive field strength can be measured. If the latter is the best, switch to the transmitter "Ismaning" and this study is practically inaudible to the listener.

Each list consists of a series of digital information blocks, which in FIG. 1 is indicated as horizontal lines within the list. Each information block consists of a few information, as indicated by the vertical division of the list into a left and a right half. The first labeled "head" of 25 blocks in each list contains in the left block half the number of the alternate frequencies within that list. In the list of transmitter # 1 with four alternate frequencies, the head contains the number 4, in the list of transmitter # 29 with seven alternate frequencies, the head contains the number 7. In the right block half, the head of each list contains the operating frequency of the the responding list sends.

In the list of transmitter # 1 with operating frequency 98.5 12 DK 175172 B1 MHz, frequency information 98.5 MHz is indicated in the right half of the head. In the list for transmitter # 29 with the operating frequency 97.9 MHz, the frequency information is transmitted in the head 97.9 MHz.

5 Up to now, compliance with the method of DE Patent No. 34 32 848 has continued

in this case, two alternate frequencies are transmitted in the following blocks of each list, so that in the case of list # 1 with four 10 alternate frequencies, two blocks of 2x2 = 4 alternate frequencies are followed.

In contrast, in the present embodiment of the invention, in each subsequent block, the operating frequency corresponding to the list is transmitted together with an alternate frequency.

This pair thus contains the operating frequency as the address of the alternative frequency in question, which has the advantage stated above that the operational security is drastically increased, although the number of blocks needed for each list following the head doubles.

Thus, in the list of transmitter # 1, after the head instead of two blocks, which according to DE patent no. 34 32 848, four blocks must now be transferred, 25 which results in a corresponding increase in the transmission time for the row of 29 considered lists. . Since this transmission time is equal to the cycle duration for each row of lists, one would think that the reception security of transmission disturbances would be impaired as a result of this extension of the cycle duration. However, as already stated, this assumption is incorrect, so that the surprising effect is found that, in the method according to the invention according to this embodiment, despite the extension of the cycle duration, a clear improvement in the reception security is obtained. to the list method and the matrix method.

5 In the case of transmitters whose operating frequency is not in the 100 kHz raster but in between (so-called offset frequencies), e.g. 92.85 MHz, is transmitted at the head of the list in question, not the frequency of operation, but a special information, 10 a so-called "fill code" according to the above-mentioned document from the European radio station. In the subsequent block, the offset frequency is first transmitted, e.g. 92.85 MHz, and then a qua page frequency, e.g. 92.8 MHz. This quasi-drift frequency is transmitted in the following blocks in the first position as the address of the alternate frequencies.

A further departure from the transfer rule specified in the drawing for the individual lists will appear if one of the alternative frequencies is a 20 offset frequency. In this case, in the block in question, instead of the operating frequency, the offset frequency of the alternate frequency is transmitted together with the quasi-alternative frequency contained in the 100 kHz raster.

For identifying alternative frequencies for such transmitters, which, within the framework of regional programs for some periods of time within a transmit day or transmit week, are disconnected from the corresponding transmitter chain, e.g. transmitters there from 7 p.m. From 6 am to 12 noon 30 the program "Bayern 3" will be broadcast, from 1 to 3 pm. 12 noon to 1.30 pm regional program "Neues aus Schwaben" and from 1 pm. From 13:30 to 24:00 again the program "Bayern 3", it may be appropriate in the corresponding block that the order of operation frequency and alternative frequency, ie first transmit the alternative frequency, and then the address "operating frequency" may be changed.

Each list is adapted to the transmitter in question 5 and contains a maximum of 25 frequencies corresponding to the agreement within the European radio station, generally fewer. At the beginning of each list, the operating frequency represents the corresponding transmitter, ie. in the list for transmitter # 1, at the beginning 10 states the frequency of transmitter # 1, e.g. 98.5 MHz.

As mentioned, the displayed row of 29 lists is transmitted from each transmitter in the transmitter chain as a data signal.

The receiver receives and decodes the transmitted data signal, ie. the series of lists of alternative 15 frequencies. In order to select the valid list for the currently tuned transmitter from the received series of lists, the receiver only needs to compare the first frequency in each list with the current tuning frequency, which can be done even in a very short time even at 20 29 lists. This selection can be done either on-line or offline, ie. without or with intermediate storage of the received row of lists. In a preferred embodiment, the selected list is stored in all cases.

25 When processing the received and optionally stored row of lists, the receiver selects the list whose first frequency (which is equal to the operating frequency of the corresponding transmitter) corresponds to the instantaneous tuning frequency.

30 If the first frequency for several lists matches the set operating frequency, all these lists must be selected. Only the list (s) of choice in DK 1517172 B1 is turned to the subsequent optimization of the vote.

This tuning process is done either by an appropriate order from the listener or automatically, e.g. when 5 the currently received transmitter is no longer received satisfactorily. In the tuning process, the receiver is automatically tuned to the alternate frequencies listed in the selected list (s) and selects the alternate frequency that provides the best possible reception. By means of the transmitted data signal RDS, a fast optimization of the tuning of mobile receivers can also be carried out for transmitter chains with more than the specified maximum number of alternative frequencies, without the need for filtering out and re-storing of frequency lists at the position of the bisenders.

FIG. 2 shows a block diagram of a receiver for a method according to another embodiment of the invention. In this connection, reference is made to the FIG. 1, although in this second embodiment it is not essential whether the additional information is transmitted in digital form.

The radio gain signals received by an antenna 1, which contain additional data, are supplied to a tuner 2 and a tuner 3. The tuner 2 is part of a radio receiver apparatus with an intermediate frequency amplifier 4 for the intermediate frequency delivered by the tuner, and a detector 5 for generating the low frequency signal and an amplifier 6 for the low frequency signal as well as with a loudspeaker 7 for acoustic reproduction. For the signal path, e.g. to the output of the tuner 2 is connected a coupling 10 for selecting the 57 kHz carrier wave and connected to a coupling 11 for generating the data. This data is supplied to a memory 12. In this memory 12 the alternative frequencies (AF) of the transmitter received with the receiver 2 are constantly input.

The tuner 3 serves to continuously scan the frequency range that can be received by the tuner 2. The high- and medium-frequency output signals from the tuner 3 are also supplied to the storage 12. The frequencies entered by the tuner 3 are constantly compared with the corresponding stored frequencies to provide of an indication of the transmitter that is currently best received. The frequency to which tuner 3 is to be set is determined by memory 12 by means of a microprocessor 13 over a line 14, and tuner 3 is tuned accordingly.

A coupling 15 serves to measure the field strength of each received transmitter. As soon as the field strength measurement shows that the signals from another transmitter have a larger field strength than the signals from the transmitter to which the tuner 2 is set, the tuner 2 is switched over a line 16 to the transmitter which currently has the greatest field strength.

With the coupling described so far, it is possible that due to interferences, e.g. distortions of the acoustically reproduced audio signal occur. Such interferences mostly occur near very powerful transmitters. Also, due to a large field strength at the immediate receiving site, an override of the receiver may occur, thereby distorting the acoustic reproduction.

17 DK 175172 B1

For example, in a The method known from DE Patent No. 34 48 043 allows for the selection of a transmitter a fully automatic tuning without the user's involvement to the transmitter with the same program which is best received at the instantaneous receiver position, ie. has the greatest field strength.

For this purpose, each transmitter will not only radiate its own list, but also sequentially the lists of all other transmitters in the same transmitter chain, the 10 operating frequencies of each transmitter being indicated at the beginning of each list. Thus, upon receipt of all lists on the basis of its immediate polling frequency, the recipient may select the list belonging to the currently receiving transmitter, 15 comparing the polling frequency to the first frequency of each list within the list row. Furthermore, the receiver also notes the alternate frequencies at which, when it leaves the supply area of the currently tuned transmitter, 20 can continue to receive the same program without the need to examine the alternate frequencies in the other lists. In this way, switching to another transmitter in the same transmitter chain can usually be carried out very quickly.

25 However, just when receiving transmitters with large field strength, the acoustic reproduction can be distorted. This can be done, for example. due to oversteering due to excessive receiving field strength, or to interference phenomena due to reflections.

Therefore, in the present embodiment of the invention, it is provided that it is possible to make a transmitter setting while retaining the automatic switch to other transmitters which broadcast the same program, thereby providing acoustic distortions in the wide extent is avoided or diminished.

By means of a coupler 17, in the microprocessor 13 a coupling state is produced, whereby not the most powerful transmitter, but a weaker transmitter, especially the second strongest transmitter, is used for comparison with the set operating frequency transmitter.

By designing coupler 17 as a reset key, it is achieved that the setting of the apparatus on a transmitter with less field strength than the instantaneous greatest field strength can be recalled when the transmitter near or interference zone is exited. A repeated coupling process is thereby facilitated. The effect of coupler 15 17 on microprocessor 13 can also be designed such that all transmitters corresponding to the stored alternate list can be set successively with decreasing field strength by briefly operating the coupler 17 several times. For a longer operation of the coupler 20 17, e.g. for several seconds, the reset process can be triggered.

The tuner 3 in FIG. 2 may be of a different design than the tuner 2, since its actual task is merely to tune the frequency band to control any 25 stronger transmitters. Thus, no signal quality is required.

It is also possible to carry out a field strength switch in the form described using only one tuner, whereby, during the interrogation process, transmitters with inferior field strength can be received.

FIG. 3 shows, as a third embodiment of the invention, a change of the embodiment shown in FIG. 2 illustrates 19 DK 175172 B1 coupling, wherein two equal tuners 2 and 3 are connected in two separate receiving branches A and B, each delivering a low frequency output signal NFA and NFB to a low frequency switch 18 which transmits one of these 5 signals to a low frequency amplifier. 6 and a loudspeaker 7. From the tuner 2, the data signals (e.g. from the RDS data stream) are separated by a selection circuit 10, 11 and they are supplied to the storage 12 with the microprocessor 13. From the tuner 3 the data signals are also separated and the The storage 12 is also supplied with the microprocessor 13. The tuner 2 can be tuned by manual or random activation. The tuner 3 is interrogated by the storage 12 or the microprocessor 13 over the line 14, corresponding to the stored alternative 15 list.

Determination of the transmitter with the greatest field strength occurs in a coupling 15 by comparing the received signals from the tuner 2 and the tuner 3. If the tuner 2 is not tuned to the transmitter that can receive 20 with the optimum field strength, the tuner 3 acquires this transmitter with the strongest field strength, and its low frequency output signal NFB is applied across the coupler 18 to the low frequency amplifier 6 and the speaker 7.

In this switching mode, the tuner 2 is interrogated by a line 20 of the microprocessor 12/13 corresponding to the frequencies stored in the alternate list.

The low frequency signals NFA and NFB are applied to a coupling 19 to compare the modulation of the two signals. In this modulation comparison coupling, the modulation content of the transmitter with the greatest field strength is compared with the modulation content of the transmitters selected from the alternate list 20 DK 175172 B1. Conveniently, this comparison is made with the second most powerful transmitter in the list.

The comparison can be made by directly comparing the temporal course of the low-frequency voltage or by comparing the envelope curves for the two low-frequency signals. If the transmitter with the strongest field strength due to reflections exhibits sudden modulation increases or modulation drops and cuts of the low frequency due to oversteer, the coupler 18 is automatically switched by the microprocessor 12/13 to the second most powerful transmitter so that the distortions cannot be recognized by the user. If the two signals are identical, the transmitter with the greatest field strength remains connected. Hereby, the coupler 18 can be switched continuously to the other receiver A, B, to the other receiver B, A, depending on the microprocessor control. Only by manual or other action from the user does the tuner 2 again gain starters, and then be subjected to the automatic RDS controlled mode of operation.

Claims (11)

21 DK 175172 B1 A method of transmitting digital information in a radio signal as tuning aid 5 in radio reception, wherein the digital information contains a series of separate to each transmitter in a transmitter chain or to these individual transmitters optimized lists of alternative frequencies, characterized in that by transmitting each list as a result of digital blocks, each with two digital information per rule, (a) in the first block of each list, information is transmitted on the number of the alternate frequencies 15. the list in question, as well as the operating frequency of the transmitter belonging to the list; and b) in the remaining blocks in each list. the operating frequency of the transmitter corresponding to the list as well as the alternate frequency. Method according to claim 1, characterized in that on the receiver side, the operating frequency transmitted in the first block and / or the remaining blocks for a list transmits alternative frequencies to the relevant transmitter chain for a unique, disruptive addressing. Method according to claim 1 or 2, characterized in that of the received alternate frequencies on all the frequency lists, only the alternative frequencies are stored and / or used for the tuning, the associated operating frequency of which corresponds to the radio frequency receiver's momentarily set reception frequency. 22 DK 175172 B1 Method according to one of Claims 1 to 3, characterized in that the operating frequency of the remaining blocks is located in front of or follows the relevant alternative frequency. Method according to one of claims 1 to 4, characterized in that the received digital information undergoes an error correction and that based on the incorrectly corrected digital information, the alternative frequencies 10 are made on the basis of it in or to each list. optionally several times transmitted transmit operating frequency. Method according to claim 6, characterized in that bit errors detected by the received digital information are used alone or together with the receiving field strength for quality assessment. A method according to claim 6, characterized in that the bit errors are used to evaluate program signal distortions in the sense that a) in the case of sudden bit errors leading to multipath reception or interference, b) in the case of uniformly distributed errors there are disturbances resulting from c) the degree of all interference is derived from the block error rate of the block structured RDS data signals, taking into account the selection criteria for each alternate transmit frequency and the instantaneous receive frequency: d) If all frequencies examined essentially exhibiting only sudden occurrence, or only uniformly distributed bit error, they are compared with respect to their block error rate with each other, whereby the frequency with the lowest block error rate is selected for receiver tuning, e) if the frequencies studied exhibit different bit error advantages. first, those frequencies which essentially exhibit uniformly distributed bit errors are first preselected - possibly depending on the fact that a predetermined maximum allowable block error rate is not exceeded at these frequencies - and then the preselected frequencies are compared with respect to their block error rate, whereby the preselected frequency that has the lowest block error rate is selected for receiver tuning. Method according to one of Claims 1 to 7, 15, characterized in that the alternate frequency that momentarily offers the best possible reception is tested as to whether it allows an acoustically acceptable reproduction and that, in the case of the tested alternative frequency only 20 allows an acoustically distorted reproduction, another alternative frequency is selected. Method according to claim 8, characterized in that manually adjustable means are used for selecting another alternative frequency. Method according to claim 8 or 9, characterized in that means for selecting a different alternative frequency are used which can be adjusted by a signal, wherein said signal, possibly also weighted differently, is derived from both the comparison of the received ones. field forces, as of comparison of low-frequency distortions associated with the field forces. Method according to one of claims 1 to 24, characterized in that the alternative frequencies are detected on the receiver side by evaluating a program identification code (Pi code) received in the digital RDS signal, the receiver part 5 performs a transmitter search run and compares the PICs for the RDS signals received at each transmitter frequency so that one's PI codes identify the frequencies at which the same program signal can be received.