MXPA00010357A - Method for processing transmitter and program related data in an fm rds receiver - Google Patents

Abstract

Method for processing transmitter and program related data in an FM RDS receiver and receiver executing the method, providing a band scanning search for detecting FM RDS transmitters exceeding a predetermined reception quality level. To enhance efficiency in data processing and use of storage capacity, transmitter related data including tuning data is stored separately from program related RDS data. Per each detected transmitter a quality factor indicating the quality in reception quality thereof is being allocated to each detected RDS transmitter and stored in a first memory bank, along with the relevant tuning data. Per each program identification code carried in the RDS data of the so detected transmitters program related FM RDS data are being stored in a second memory bank, a linkage code defining the storage address within the second memory bank containing the program data carried by the relevant FM RDS transmitter being allocated to the transmitter data of each FM RDS transmitter and stored in the first memory bank.

Description

METHOD FOR TREATING DATA RELATED TO TRANSISTORS AND WITH PROGRAMS IN AN RDS RECEIVER FM DESCRIPTION OF THE INVENTION The invention relates to a method for processing data related to transmitters and to programs in an FM RDS (Radio Data System) receiver (frequency modulated) and to a receiver that executes the method. The RDS FM broadcasting standard is defined in "Specification of the Radio Data System FM RDS for VHF-FM Sound Broadcasting" (Specification of frequency modulated radio broadcasting system for audio broadcasting in very high frequency - fre cue modulated channel) of the European Broadcasting Union (EBU), in the Tech 3244-E document of the EBU, March 1984, and updated in subsequent revisions thereof. Reference is made to this document for a correct understanding of the meaning and definition of the various terms and abbreviations used in the following, in relation to the RDS standard in FM.

An FM RDS receiver that executes the aforementioned method is, in itself, known, for example by European patent 0 333 194. The known FM receiver is an FM RDS receiver with dual tuner having a first tuner or tuner main and a second tuner or auxiliary tuner. The main tuner is used to tune the receiver to a broadcasting broadcast station with a desired audio program and to process the signals of the audio program to play sounds. If the transmitter also transmits RDS data, then the main tuner will also extract the RDS data carried by the signal received from the RDS transmitter, in particular a list of alternative frequencies (? F). Said list provides tuning data of transmitter frequencies that carry the same program as that of the receiver actually tuned. The auxiliary tuner is used to monitor the quality of reception of the transmitter signals in each of these AF. For this, the auxiliary tuner is switched in sequence to each AF of the AF list to measure the reception quality of the transmitter signals in the respective AEs. This information of reception quality is stored in a memory and continuously updated in scanning cycles s e cu e c i a 1 e s. When the received transmitter signal deteriorates, the main tuner is automatically switched in its tuning to the AF stored in the memory that has the highest reception quality. The options of the previous automatic tuning of the main tuner tuning are limited to the correctly received AFs and the SDs. An object of the invention is to eliminate this limitation and increase the range of tuning selection options. According to the invention, a method for processing data related to transmitters and programs in an FM RDS receiver is therefore characterized by a search by band scan to detect FM RDS transmitters that exceed a reception quality level. predetermined, by storing in a first memory bank data related to transmitters for each of said transmitters, including the tuning data and a quality factor that: indicates the reception quality thereof, by storing in a second data memory bank RDS in FM related to programs for each program identification code received, and by assigning to the transmitter data of each FM RDS transmitter stored in the first memory bank, a link code defining the storage address within the second memory bank containing the program data carried by the relevant FM RDS transmitter. Thanks to the measure according to the invention, no use is made of RDS data of AF in FM. Instead, the second tuner is used to scan in sequence through the frequency band looking for any received broadcast broadcasting station with a suitable RF signal reception quality., including FM RDS broadcast stations. When one of such FM broadcasting transmitting stations is detected, the scan is interrupted to read the data related to the aforementioned transmitter in the first memory bank and, in the case of an FM RDS signal, to also read the RDS data in FM of the second memory bank. The division in the storage of the data related to the transmitter and the data related to the program allows to achieve an efficient use of the storage capacity, while preserving any tuning selection option for the user, as will be explained in what follows in more detail. The storage of RDS program data allows, for example, to provide AF switching without making use of the AF lists included in the RDS data and / or to extend the definition of alternative programs of audio programs strictly identical to non-identical programs within a certain category of RDS programs, such as PTY (Types of Programs). An FM RDS receiver that executes the method according to the invention comprising a first and a second tuner circuitry for receiving and processing, respectively, RDS FM audio and data signals, comprising tuning control means for varying the tuning frequency of the second tuner circuit in a frequency band for detecting FM RDS transmitters received with a reception quality exceeding a predetermined quality threshold level, by automatically switching the first tuning circuit in its tuning of ur ^ zrr £ sr, 3i & The first FM RDS transmitter actually received at a second FM RDS transmitter detected by the second tuner circuit when the reception quality of the first FM RDS transmitter decreases below a predetermined level, is characterized by a processing unit which stores at a first memory bank, for each selected FM RDS transmitter, data related to the transmitter that includes the tuning data and a quality factor that indicates the reception quality thereof and, in a second memory bank, RDS data in FM related to the program for each received program identification code, and to assign to the transmitter data of each FM RDS transmitter stored in the first memory bank a link code defining the storage address within the second bank of memory containing the program data carried by the relevant FM RDS transmitter. Preferably, the method is characterized in that the scan by band scan is repeated subsequent scan cycles, updating the data related to transmitters, with respect to its quality factor and being deleted from the first memory bank when the quality factor decreases below a predetermined quality threshold level. An FM RDS receiver executing said preferred method is characterized in that the tuning control means controls the tuning of the second tuner circuit to repeat the scan by band scan in subsequent scan cycles to update the quality factor of each detected transmitter, the storage positions of the first memory bank related to transmitters whose quality factor decreases below a predetermined quality threshold level are suppressed. This measure further improves the efficiency of the memory capacity utilization without losing the information as to which transmitter frequency should be chosen in case the actually received transmitter signal falls below said predetermined threshold level. Another preferred method is characterized by an automatic tuning switch from the first FM RDS transmitter to a second FM RDS transmitter when the signal of the first FM RDS transmitter decreases below a predetermined field strength threshold level, being selected the second FM RDS transmitter among the FM RDS transmitters of the first memory bank having the same link code as the first FM RDS transmitter. An embodiment of an FM RDS receiver that performs the most preferred method, mentioned last, is characterized in that when selecting the second transmitter the processing unit is limited to FM RDS transmitters having the same link code as the signal of the same. first FM RDS transmitter. Thanks to this measurement, the alternative frequencies (AF), that is, the transmitter frequencies that carry the same audio program as the one to which the first tuner circuit is actually tuned, are not derived from the list of AF included in the RDS data in FM, but the transmitters that have the same link code associated with them. The AF can be determined very quickly with maximum reliability in terms of reception quality, that is, the maximum quality factor and / or the maximum intensity of the amp. These and other aspects and advantages of the invention will be described in greater detail below with reference to the description of preferred embodiments and, in particular, with reference to the accompanying drawings, in which: Figure 1 is a coding structure of RDS base band in FM; Figure 2 is a block diagram of an FM RDS receiver with dual tuner, according to the invention; Figure 3 is a functional diagram of the list structure provided by the first and second memories, as used in the FM RDS receiver of Figure 2; Figure 4 is a flow chart illustrating the method according to the invention in execution by the FM RDS receiver of Figure 2. Figure 1 shows the RDS baseband coding structure of FM in the data format of the FM OA RDS Group type, as defined more specifically in the aforementioned EBU document. The OA Group type is intended to provide basic information about tuning and switching and other similar Group types consist of four blocks B1-B4, each of which contains a part of 16 bits carrying information and a part of 10 bits of information. check and displacement word, respectively C1-C4. The check and scroll word parts C1-C4 provide error protection and group and block synchronization information. In the OA Group type, the information carrying parts of the blocks B1-B4 comprise, respectively: In block 1: a program identification code (Pl); In block 2: in this order, a group type code, a traffic program identification code (TP), a traffic notification code (TA), a program type code (PTY); In block 3: alternative frequency codes (AF); In block 4: a program service name (PS) segment. - -s.i-5sa - »8» iefea% f < tft J * -, The RDS standard in FM provides a type of OB Group, which differs from the type of Group OA in that in block 3 the PI code is repeated. For detailed information about specific questions about these RDS elements of FM, reference is made to the aforementioned EBU document. Figure 2 shows a block diagram of an FM RDS receiver according to the invention and which, coupled to an antenna 1, comprises a first and a second tuner circuitry 2 and 3 for processing, respectively, RDS audio and data signals. in FM. The tuning frequencies of both first and second tuning circuits, 2 and 3, are controlled through tuning control means 10, 11, 25 including a central processing unit (CPU) 25 and an electronic control module 11. / S (input da / sa 1 i da) of a microprocessor 12 and a control bus 10. By manually operating one of the keys 21-24, the tuning frequency of the first tuner circuit 2 can be set, via an I / O module 20 interconnecting with the user, at the transmitter frequency ft of a station of the desired FN broadcast. The key 21 activates an automatic storage function ^ the key 22 activates an up / down search, the key 23 is used to connect / deactivate the reception of traffic messages and the key 24 is used to activate a search for programs within the same PTY category as the one actually received. These functionalities require the use of a program memory 26 for storing program software and a timer module 28 and are themselves known by the prior art FM RDS receiver mentioned below. The first tuner circuit 2 allows the selection and de-activation of a desired FM broadcasting RF signal in a baseband and comprises means (not shown) for measuring the reception quality of the RF signal in FM received. A quality factor that reflects said reception quality is supplied by the quality level line 14 to a AD converter module (ana 1 logic / digit 1) of the microprocessor 12, to be further treated as described in what follows . Depending on the content of the received FM broadcast signals, the baseband signal may comprise an RDS signal and / or a monophonic or multiplex signal. The baseband signal is supplied by a signal line 5 from an output of the first tuner circuit 2 to a digital signal processor 6. The digital signal processor 6 comprises means (not shown) for processing audio signals, for processing monaural audio signals and, optionally, for smu 1 tip 1 e xa r stereophonic multiplex signals in stereophonic audio signals left and right, and is coupled to an audio amplifier 8 and a set 9 of speakers for reproducing the audio signals thus derived. The digital signal processor 6 is coupled to an RDS encoder 7 for decoding RDS data contained in the received FM broadcast signal. The decoded RDS data is supplied by an RDS data line 18 to an RDS data I / O module 19 of the microprocessor 12. The processing of the RDS data is performed under the control of the CPU 25 of the microprocessor 12. The second tuner circuit 3 is used to select and demodulate RDS signals from a radio broadcast RF signal ---.- »< , -a-at-rfe »* ^ -» -.

FM and, therefore, is also indicated as TS. data tuner. An RDS decoder 4 following the output of the second tuner circuit 3 derives RDS data from the demodulated RDS signal. ^ The RDS data is supplied by an RDS data line 16 to a microprocessor RDS data I / O module 17 12. Apart from this, the second tuner 3 also comprises means (not shown) for measuring the reception quality of the received FM broadcasting RF signal. A quality factor that reflects said reception quality is supplied by a quality level line 13 to the AD converter module of the microprocessor 12, for its proper treatment and storage. The tuning frequency of the second tuner circuit 3 is automatically varied to scan the FM radio broadcast reception band between 87.5 MHz and 108 MHz. Upon first reception of an FM broadcasting station with an FM reception quality that exceeds a certain predetermined threshold level, qt, scanning stops to perform measurement and storage operations under the control of the CPU 25, ^ ¿S? ÍSi ^ ^! ^^^! as described in the following with reference to Figure 3: 1. the tuning data of fx is stored in a storage address Tx of a first bank Ml of memory, included in a data memory 27 of the microprocessor 12; 2. the quality of reception of fx is measured and, from it, a quality factor that is stored in Tx is derived; if RDS signals are being received, then, in addition: 3. a link code is assigned to fx in Tx in the first bank Ml of memory, this link code refers to the storage address Ny of a second bank M2 of memory included in the data memory 27; 4. The Pl code of the RDS signals carried by fx, as well as the PTY, TA, TMC, PS and / or PS Mask codes are stored in Ny, in the second memory bank M2. The data stored in the first memory bank Ml are typically related to the transmitter and together form a list in a transmitter structure, also referred to hereafter as a list of transmitters. The data stored in the second memory bank M2 are typically related to programs or networks and together form a list in a structure of Pl, also referred to hereafter as a list of program or network data. The parameters for the quality factor may include the field strength, but also multiple pathways (lack of them) and other environmental pollution sources and the aforementioned predetermined threshold level, are selected in such a way that the FM broadcast signals in RF exceeding this level may be treated properly without giving rise to receiver failures or noticeable deformations of the signal. In the FM RDS receiver of Figure 2, the quality factor is derived from the field strength of the RF reception signal, indicating fx with sx. If in a subsequent scan cycle fx is no longer detected, then all data from the first bank Ml of memory related to f > will be eliminated, because the quality factor sx has decreased below a threshold level of 'quality st. If the link code l and fx are not shared by other transmitters, then the RDS data of the second memory bank M2 will also be removed. The deletion of data from the first and second memory banks Ml and M2 can be done by deleting them or by releasing the relevant storage positions for the storage of new data, so that it is written on the obsolete data. The storage of data related to the transmitter in the first bank Ml of memory separated from the storage of data related to programs or with networks in the second bank M2 of memory, allows an efficient use of the memory capacity, because the transmitters carrying the same PI code share the same storage address in M2. For each different PI code, all other related RDS codes, such as, for example, PTY, TA, TMC codes, are stored only once. In addition, such separation in storage also allows an effective treatment of the data, in particular for the purpose of performing an AF search, that is, to find an alternative frequency carrying the same RDS program as that to which the first tuner circuit 2 is tuned in reality. Since all of the data necessary for the AF search is already available in the first memory bank Ml, the second memory buffer of the AF search operation can be excluded. For example, the functionality of AF requires that the AF with the highest quality (f) of reception be known at all times, in order to automatically switch the tuning of the first tuner circuit 2 from an RDS transmitter ft, with which it is really tuned. the first tuner circuit 2, at said fh, when the reception quality of ft decreases below the predetermined threshold quality level cited above, st. This means that the quality factor of transmitters carrying the same program as the RDS transmitter ft, with which the first tuner circuit 2 is actually tuned, must be monitored continuously. According to the invention, this monitoring is limited to transmitters with the same link code as the RDS transmitter ft. The use of link codes in the AF search according to the invention eliminates the need to decode and store the AF data transmitted in block 3 of the above-mentioned OA RDS Group type. Since all the data related to the transmitter is stored in the first memory bank Ml, all the tuning selection options based on the reception quality are preserved. For example, by activating the option of "automatic storage" by means of the key 21, the quality factors of the various transmitters stored in the first bank Ml of memory can be compared with a certain level of threshold, chosen so that it is exceeded, for example, 6 transmitters, which can be RDS or non-RDS transmitters. The tuning data of these transmitters must be stored under the automatic storage feature and they are requested when pressing the key 21. As a criterion for this threshold level, the quality factor s can be used. These are also applicable to the determination of a threshold level for use in the up / down search of traders, which can be activated by the key 22. As the data related to the program connected to the code of the signals Received RDS are stored in the second memory bank M2, all tuning selection options based on that RDS data are also retained. For example, the availability of codes of ^ - Utt --- á - ¿íí PTY allows a conventional search of PTY transmitters, which can be activated by the key 24. The receiver can be adjusted, also, to reproduce traffic messages by pressing the key 23 As a criterion for selecting an RDS broadcasting station that transmits appropriate traffic messages, the field strength is preferably used among those with the traffic news label. In practice, the transmitter that is best received (that is, with the maximum field strength) is the closest to the receiver's situation and the traffic messages of that transmitter are, therefore, the most interesting for the user. Figure 4 shows a flowchart of an algorithm for practically executing a method for tuning the reception of broadcast signals to an FM RDS transmitter using data related to transmitter related programs and data, according to the invention, in which is referred to in Figure 3. Operations al-a30 of this flowchart have the following meaning: ^ & ^ and al When the radio is turned on, the algorithm starts. a2 The second tuner circuit 3 is initialized to perform a first search scan, starting at the lowest frequency of the FM band transmitter (87.5 MHz). The first and second memory banks Ml and M2 are initialized to store, respectively, data related to the transmitter and RDS program data in the transmitter (T) and program or network (N) lists. a3 The tuning frequency of the second tuning circuit 3 is varied until a transmitter fx is received. The scanning procedure is interrupted to measure the field strength and to assign and store a factor sx that reflects the field strength in the list T of the first bank Ml of memory, in the storage address Tx. a4 Does sx exceed a predetermined threshold level st (for example, st = 1)? - If so, then go to alO. Otherwise, go to a5. a5 The field intensity level (sx) is not good enough. Tx is checked for the presence of certain data that could have been assigned to fx in a previous scan cycle. If fx has previously appeared as an RDS transmitter, then Tx would contain a link code. Said link code, for example ly, refers to the storage address Ny of a list N of the second memory bank M2, in which the RDS data associated with the PI code carried by the RDS transmitter fx are stored. Does Tx contain the link code ly? - If so, go to aß. If not, then fx has not previously been recognized as an RDS transmitter: go to a9. a6 Leave this link code free, as well as an eventual Tx RDS tag. a7 There may be more transmitters linked through the same link code and the same storage position in the Ny address of the list N of the second memory bank M2. Is it shared by more transmitters ?. If it is, then go to 9. Otherwise, go to 8. a8 Tx of the first memory bank Ml has an univocal link through ly and Ny of the second bank M2 of memory: also let Ny free. a9 Resume the scan operation. When the upper limit of the FM band (at 108 MHz) has been reached, repeat the scan cycle starting again (a3) from the lowest transmitter frequency (87.5 MHz). alO The field strength factor sx of fx is correct. Wait a while to verify that fx carries RDS data and, if so, pick it up. all Check whether the program identification code (PI) or PIy program identifier included in the fx RDS data has been received correctly. If so, go to al2. Otherwise, go to al8. al2 Check if the same PI code, PIy, has been previously received and stored in the list N of the second memory bank M2. If so, go to al3, otherwise, go to al4. al3 Store in the storage position Tx of the tuning data of fx in the list T of the first memory bank Ml, defining the link code l and the storage address Ny of PIy in the list N of the second memory M2. al4 The received PI code is new, for example PIz: the list N is scanned in M2 to check if the list N is occupied in SL -------------- i ii-ilisaiMKii - ? --- íá ----- É ---------- totality. If so, go to al7, otherwise go to al5. al5 In the N list it seems that free storage capacity is available in, for example, storage address Nz. A new link code lz is defined which connects Tx of Ml with Nz of M2 and is assigned to fx. This new link code lz is stored in the storage position Tx of the tuning data of fx in the list T of the first memory bank Ml. al6 Store all received RDS data, carried by the RDS transmitter fx in Ny, or in Nz, as the case may be. al7 Indicate, without having a link code, that fx is an RDS transmitter, establishing an RDS NW tag in Tx. al8 No PI code is received. Check whether in the storage position Tx of the fx tuning data of the first memory bank Ml, a link code is stored. If there is, go to al9. If there is not, then fx is a transmitter without RDS features: go to a9. al9 A link code is available, so that fx is an RDS transmitter. Check if an RDS NW label is set at the Tx position S ^ j ^ ^ ^ of storage of the tuning data of fx in the first memory bank Ml. If there is, go to a20, otherwise, go to a21. a20 NW is established: delete NW from the storage position Tx of the tuning data of fx in the first bank Ml of memory, but keep the link code. a21 NW has already been deleted, delete the link code. a22 Do other transmitters in Ml share the same link code? If they do, go to a9, otherwise go to a23. a23 Delete all data from the memory location in the storage address of the second memory bank M2 (Ny or Nz, depending on the case), which were connected by means of the link code with Tx. The method applied in the above algorithm makes use of the RDS NW tag to preserve the storage of RDS data in the second memory bank M2, carried by a detected RDS transmitter, retaining them until storage capacity in M2 can be available. The RDS NW label can be dispensed with if M2 offers ^ &^ ^ ^^^^^^ j ^ gg enough storage capacity to store all the PI codes that can be received. In order to understand the invention, it is not necessary to have knowledge about the practical implementation of the different circuitry or the functions mentioned above in relation to it, such as, for example, tuning control means that provide repetitions of cycles of search exploration, the measurement of the quality of reception and the derivation of a quality factor from it, the selection 1 / of transmitters that can be properly received, the extraction of RDS data of different categories from of the received RDS signals, the storage of the data related to transmitters and with programs in M1 and M2, the switching of the tuning of the first tuner circuit 2 to an alternative frequency, etc., etc. For further details in this regard, reference is made to the RDS FM radio receiver type VDO RC 959 RDS. Furthermore, the invention can be applied perfectly, while excluding any historical influence of the determination of the quality factor, for example using the instantaneous value of the reception quality as a basis for the quality factor. The invention requires that the first and second memory banks, Ml and M2, be organized to function as separate storage means, allowing Ml and M2 to be physically included in a memory or distributed in various storage devices, depending on the CPU programming 25.

Claims (6)

1. Method for processing data related to transmitters and programs in an FM RDS receiver, characterized by a band scan search to detect FM RDS transmitters exceeding a level, of predetermined reception quality, by storing in a first memory bank data related to transmitters for each of said transmitters, including the tuning data and a quality factor that indicates the quality of reception thereof, by storing in a second memory bank RDS data in FM related to programs for each identification code. of received program, and by assigning to the transmitter data of each FM RDS transmitter stored in the first memory bank, a link code defining the storage address within the second memory bank containing the program data carried by the relevant FM RDS transmitter.

2. Method according to the claim 1, characterized in that the search by band scan is repeated in scan cycles. > - ~.? Í? *? «? ~. *? £ AtA *. ~~ ..--- subsequent, updating the data related to transmitters, with respect to its quality factor and being deleted from the first memory bank when the quality factor decreases below one level of the predetermined quality threshold .

3. Method according to claim 2, characterized by an automatic tuning switch from a first FM RDS transmitter to a second FM RDS transmitter when the signal of the first FM RDS transmitter decreases below a predetermined quality threshold level, the second FM RDS transmitter being selected from among the FM RDS transmitters related to the data stored in the first memory bank having the same link code as the first FM RDS transmitter.

4. RDS FM receiver comprising first and second tuner circuits for receiving and processing, respectively, RDS FM audio and data signals, comprising tuning control means for varying the tuning frequency of the second tuner circuit in a ^^^^ fi¡ ^ yg¡gjgj b frequency band to detect received FM RDS transmitters with a reception quality exceeding a predetermined quality threshold level, the first tuner circuit automatically switching on its tuning of a first RDS transmitter of FM actually received to a second FM RDS transmitter detected by the second tuner circuit when the reception quality of the first FM RDS transmitter decreases below a predetermined level, characterized by a processing unit storing in a first memory bank , for each selected FM RDS transmitter, data related to the transmitter that includes the tuning data and a quality factor that indicates the quality of reception thereof and, in a second memory bank, FM RDS data related to the program for each program identification code received, and to be assigned to the transmitter data of each FM RDS transmitter stored in the first The memory bank has a link code defining the storage address within the second memory bank containing the program data carried by the relevant FM RDS transmitter.

5. FM RDS receiver according to claim 4, characterized in that the tuning control means controls the tuning of the second tuner circuit to repeat the scan by band scan in subsequent scan cycles to update the quality factor of each detected transmitter, the storage positions of the first memory bank related to transmitters whose quality factor decreases below a predetermined quality threshold level are suppressed.

6. RDS FM receiver according to claim 5, characterized in that in selecting the second transmitter the processing unit is limited to FM RDS transmitters having the same link code as the signal of the first FM RDS transmitter. & yes ^^. SUMMARY Method to process data related to transmitters and programs in an FM RDS receiver and receiver that executes the method, which provides a band scan search to detect FM RDS transmitters that exceed a predetermined reception quality level. To improve the efficiency of data processing and the use of storage capacity, data related to transmitters, including tuning data, is stored separately from RDS data related to programs. For each detected transmitter, a quality factor, indicative of its quality of reception, is assigned to each detected RDS transmitter, a factor that is stored in a first memory bank together with the relevant tuning data. For each program identification code carried by the RDS data of the transmitters thus detected, FM RDS data related to the programs are stored in a second memory bank, a link code defining the storage address within the second bank being assigned. of memory containing the program data carried by the relevant FM RDS transmitter, to the transmitter data of each FM RDS transmitter and said code stored in the first memory bank