Automatic station selection process for RDS preselect receiver - using stored list of alternative network frequencies to initiate follow-up tuning sequence if required

The present invention relates to a Stationenwahlverfah reindeer for a Voreinstellempfänger for the Radio Data System (Hereinafter referred to as RDS preset receiver).

Radio Data System (RDS) provides öf in radio programs lic broadcasters a program end service Radio listeners that a bezüg in such a way on the mission Liche information such. as information that the Programmin halt and the like relates, multiplex-modulated and then as the data is sent and at the receiving side a GE wünschter program content can be selected on the basis of obtained by demodulating the transmitted information Data.

Radio Data System uses a subcarrier signal of 57 kHz, ie the third harmonic of the stereophonic pilot signal of 19 kHz, which has a spectral range outside the Fre quenzbandes the frequency-modulated wave assumes. Of the Subcarrier is amplitude modulated with a data signal, the broadcast of the program content and the like be solid information is significant and previously filtered and was biphasenkodiert, thereby a radio data signal it hold, and the amplitude modulated subcarrier is on frequency modulates the main carrier and out of the main beams sends. The standard of the transmission method was by the Eu pean transmission Union (EBU) suggested.

It is known from in <b>Fig.</b> 1 shown baseband coding structure can be seen that a radio data signal in repeated multiplexes consisting of 104 bits groups and transmis gen is. Each group contains four blocks of 26 Bits. Each block consists of an information word of 16 Bits and a check word of 10 bits. The group is in 16 Types (0 to 15) by the content corresponding 4 bits classified sified. Next, for each type (0 to 15) two Ver versions A and B defined.

<b>Fig.</b> 2A and 2B show Use of groups of type OA or 0B. In type 0A (<b>Fig.</b> 2A) are 16 bits comprehensive program Identification data (later known as PI hereinafter) in Block 1 arranged that and a country code, a range code a program code include; different codes that a Gruppenartkode, a Versionskode (B₀), A Verkehrsinfor mation-Sendestationidentifizierungskode (TP), a Pro program content-identification code (PTY) and the like ent hold, are in block 2 arranged, station frequency data (Hereinafter abbreviated: AF information) of power stations that the Send same program are placed in block 3, and Sen destations-name data (hereinafter referred to as PS data hereinafter) in block 4. On the other hand is different in the group Type 0B (<b>Fig.</b> 2B), only the content of the block 3 of the in Group type 0A that there the PI data in block <b>3</b> . are This means that the AF data, the power stations emitted only by the group type 0A and the PS data emitted by both the groups type 0A as well 0B will.

As already mentioned, the AF data of the network stations, which emit the same program as the currently received Station on the radio data signal group type 0A contained th. Therefore, the same program in a good Emp initial state through the so-called. "Power-over function" received and be heard without affected by disturbances will. The power-drive mode, in which, after receiving the AF Data and the PI data by demodulating the reception the signals are obtained as received an AF list and are stored, and for example, if the strength of the The received signal of the currently received station by disturbances gen from such multi-pass interference or the like falls, another station of the same station network group is selected on the basis of the previously stored AF list, and it is turned on, a check to see if the program received correctly or not in accordance is provided with the AF list, by performing a so-called. PI Überprü audit to confirm the coincidence of the PI data.

On the other hand, the RDS with an on Voreinstellempfänger sett-channel memory provided with memory areas a plurality of preset stations correspond. The AF data indicating the receiving frequency of each voreingestell th station call, and a variety of AF (AF Lists) and PI data of the same network station group aufmulti on the transmission shaft each preset station be plexiert, are in each storage area in the Preset alternate-channel memory. If any of the presets identified stations is selected, even if the signal strength is low, being the power-over function results due to the preset station concerned relevant AF list.

In the RDS Voreinstellempfänger is in Voreinstellsta tion selection previously checked the received signal level, when the receiving state of the desired preset Station is established, and the power-drive mode only performed when the received signal level is below a set level is. Since the network sequence operation executed , after audio signals such as noise or the like be already are issued, the user noticing a sign of incompatibility. On the other hand a preset Station is selected when the received signal level equal to or is higher than the set level, it may be erge ben, that the program of a station is received, the PI data to distinguish from the default PI data to, in such a way as it is.

It is therefore an object of the present invention to provide a Sta tion-selection process for an RDS Voreinstellempfänger create, with the feeling of incompatibility with the Voreinstellstationen selection process may be prevented, and in which only the transmission wave of an RDS station with the same PI data as the designated preset Sta tion received when the transmission wave of really being controlled preset station is not received.

According to the invention, a station for selection created an RDS Voreinstellempfänger, the Spei a Cher has with storage areas of a plurality Voreinstellstationen meet, and where AF data on receiving frequencies NOTE By each preset station Sen, and a plurality of AF data and PI data of the slide chen network station group before the transmission waves each set station are multiplexed in each memory area of ​​the memory is stored, said method comprising the steps of: a first step in which a Audio muting in response to a Stationsaus optional command for selecting one of a plurality of presets identified stations is started, a second step wherein, after generating the station selection command, the AF Data of a desired preset station by a decreased corresponding memory area in the memory be a given by the AF data reception frequency is set, and the muting is terminated if the preset station is an RDS station and the Emp fang signal level equal to or higher than a certain Level and is derived from the transmission shaft PI data with the corresponding data stored in the memory PI match, and a third step in which an RDS Station a receiving frequency is selected by the number of the desired preset station corresponding AF data is given, if the second Step, it is determined that the received signal level is equal to or higher than the set level and the front set station not RDS station with consistent stim PI data is coming and that the muting finishes , if the received signal level of the RDS station is equal to or is higher than the set level, and by the Transmission wave derived PI data with the vomit in memory sured corresponding PI data match.

is In the station selection process according to the invention the audio muting first initiated when the Sta tion selection command for selecting one of a plurality is generated by the preset stations, wherein a by the AF data, the desired preset station given receiving frequency is fixed, and audio- Muting is terminated when the preset Sta tion the RDS station and the received signal level is equal to or is higher than the set level, and of the transmission wave received PI data with the preset data PI match, and if on the other hand, the reception level is equal to or higher than the set level and the front set station is not the RDS station whose PI Data match, an RDS station because of the desired preset station corresponding AF list selected, and when the reception signal level of the RDS station is equal to or higher than the set level and of the obtained transmission wave PI data with the preset PI data match, the audio muting is terminated det.

The invention is described with reference to the drawing example explained in more detail; in the drawings:

<b>Fig.</b> 1 is a diagram of a basic Bandkodierstruk structure of the radio data,

<b>Fig.</b> 2A and 2B show pictures of the styles of group types <b>0</b>A or. <b>0</b>B,

<b>Fig.</b> 3 is a block diagram of a basic structure an RDS Voreinstellempfängers, with a Statio NEN-out selection process according to the invention Art leads is, and

<b>Fig.</b> 4A and 4B collectively depict a flowchart of a processing process when selecting a preset Sta tion for a selection process according to the invention, in which <b>Fig.</b> 4 shows the arrangement of the <b>Fig.</b> 4A and 4B together representing men.

<b>Fig.</b> 3 generally illustrates the basic construction of an RDS preset receiver performed on the process of the invention becomes. In the figure, a through an antenna<b>1</b> received frequency modulated multiplex broadcast wave signal of an A output stage <b>2</b> fed through which a desired station is selected. The transmission wave of the selected station is in an intermediate frequency (IF) signal and then converted via an IF amplifier <b>3</b> an FM detector <b>4</b> supplied. The input stage <b>2</b> used, for example, a PLL Synthesi zer-process with a PLL circuit, the programming a contains ble frequency divider, and leads a Stations selection process by controlling the frequency division Behaves certi- ficate of the programmable frequency reducer means a controller <b>13</b>Which will be explained later. A Ausgangssi signal of the FM-Detetors <b>4</b> is an MPX (multiplex) -Demodulie tion circuit <b>5</b> supplied. is In stereo transmission the detector output signal into audio signals for the channels L (Left) and R (right) separated. The audio signals by muting <b>18</b> directed and as Play-Au dio signals output. Muting<b>18</b> is by the control <b>13</b> on or off.

The detector output signal of the FM detector <b>4</b> is a filter <b>6</b> conducted and thereby a sub-carrier of 57 kHz, that is, a radio data signal by a biphase-ko diertes data signal is amplitude modulated and separated again by a PLL circuit <b>7</b> demodulated. The demodulate profiled output signal is a digital (D) PLL circuit <b>8th</b> and a decoder <b>9</b> fed. The D-PLL circuit<b>8th</b> generates clock pulses for Datendemodulierung due to the demo -modulated output signal of the PLL circuit <b>7</b> synchronously by the D-PLL circuit <b>8th</b> generated clock pulses. A Latch detecting circuit <b>10</b> detects a locked and an unlocked state of the D-PLL circuit <b>8th</b>, Riegelbe rich of the PLL circuit <b>7</b> and the DPLL circuit <b>8th</b> will by a detection output of the latch detection circuit <b>10</b> switched.

As in <b>Fig.</b> 3, the output data signals of the decoder <b>9</b> formed by a group unit from 104 Bits with 4 blocks of each 26 bits and is then a group / block synchronization and error detection circuit <b>11</b> supplied. In the detecting circuit<b>11</b> becomes a synchronization of the groups and blocks running on fundamentally an offset word of 10 bits, each to a Check word of 10 bits are arranged in each block. The Erfas sungsschaltung <b>11</b> also detects an error in an Informa tion word of 16 bits due to the test word. after the Data in which an error has been discovered in an error correction circuit <b>12</b> were corrected as the next stage, they control <b>13</b> supplied.

The control <b>13</b> is formed by a microcomputer. The control <b>13</b> reads the reception frequency of currently received broadcasting station designating AF data from Data sequentially in groups by the error correction circuit <b>12</b> accordingly of key inputs a preset key <b>15</b>a in an operating section <b>15</b> turned will give. The control<b>13</b> stores the read AF data in a predetermined area of ​​a memory <b>14</b> than the AF data of a preset station and sets a plurality of AF data of the same network station group as an AF list, the multiplexed to-the transmission shaft are, and further stores the data in the PI-Speicherbe rich, corresponding to each preset station. Ande hand, reads the control <b>13</b> after selecting a voreinge set station by the key input from a the preset station buttons <b>15</b>b (1 to 6), the AF data the selected preset station from the corresponding the memory area in the memory <b>14</b> and controls the Fre quenzteilerverhältnis a (not shown) program grammable frequency scaler of the PLL circuit that includes a Part of the input stage <b>2</b> forms, due to the AF data, and characterized throws the station selection process. When the transmission wave of the desired preset station as a result of bad Epfangszustandes can not be received, the net result function is performed to a station same network, which is in good receiving condition, corre result of such a preset station select relevant AF list.

On the other hand, a level detection circuit <b>16</b> vorgese hen, a received signal level (field strength) due an IF signal level in the IF amplifier <b>3</b> capture. It is a station detection circuit <b>17</b> provided to a to detect receiving station when the IF signal level in the IF amplifier <b>3</b> equal to or greater than a predetermined Level, and a detector output signal with a so. S-curve characteristic of the FM detector <b>4</b> in a vorbestimm th level range, and then a Stationserfassungssi signal output. The received signal level determined by the Pege lerfassungsschaltung <b>16</b> has been detected, and that of the Sta tion detection circuit <b>17</b> issued Stationserfassungssi signal to the controller <b>13</b> supplied.

A machining operation when selecting a preset Station as it processor of the controller <b>13</b> points out, will now reference to the flowchart <b>Fig.</b> 4A and 4B described. It is assumed that the processing routine of the <b>Fig.</b> 4A 4B and invoked by a preset station selection command and is carried out by pressing one of the preset station buttons <b>15</b>B (1 to 6) in the operating portion <b>15</b> on is given.

The processor will first switch the mute <b>18</b> into Response to the Presetting select command and performs the audio muting (step S1). Then the AF data, the desired preset station from the corresponding memory area in the memory <b>14</b> read and (not shown) in the PLL circuit Eingangsstu fe 2 supplied (step S2). Simultaneously, a PLL time encoder with a length of time that is needed to the PLL scarf lock device is set (step S3). The the PLL circuit supplied AF data are the programmierba created ren frequency divider in the PLL circuit, so that the received frequency to the frequency of the requested preset station is switched, during a Time before the PLL timer emits time pulses.

After the PLL timer has started, the timing (Step S4), the processor checks whether the transmission shaft before the set station an RDS broadcast wave (step S5). If this is the case, a reception signal level V s of the RDS station of the level detection circuit <b>16</b> decreased (Step S6). The examination of the RDS broadcast wave can be characterized be werkstelligt that will determine whether the radio data from the error correction circuit <b>12</b> can be extracted. Then, the processor checks whether the extracted reception signal level Vs is equal to or higher than a predetermined level Vth (step S7). If it is equal to or higher than Level Vth, the PI timer is on a predetermined set time (step S8). Thereafter, the PI data the RDS station removed (Step S9).

If the PI timer has started its timing (Step S10), the processor executes the PI verifications whether the extracted data with the PI in the memory <b>14</b> at the requested preset station stored PI data match (step S11). Is that the case, will mute <b>18</b> disabled and audio- Muting is terminated (step S12). Accordingly, the RDS station is selected, wherein the received signal level is equal to or higher than the set level V th and the match, the PI data and the PI data preset be right.

If it is determined in step S5 that the transmission wave of preset station is no RDS broadcast wave, or if it is determined in step S7 that the received signal level Vs is smaller than the set level V th, or if the Step S11, it is determined that the PI data under divorce, the processor reads the AF data from the previously in memory <b>14</b> stored AF list according to the gewünsch are ten preset station (step S13) and this AF data to the PLL circuit (step S14) and At the same time the PLL timer (step S15).

After the PLL timer has expired (step S16) verifies the processor determines the presence of the receiving station after by Check the station detection output of the Station detection circuit <b>17</b> (Step S17). If Emp fang station exists, the received signal level Vs. the receiving station is extracted (step S18). It will checks to see if the reception signal level V s is equal to or greater than the set level V th (step S19). If the reception signal level V s is equal to or greater than the fixed level Vth, the processor checks whether the transmission wave of the receiving station the required RDS Sendewel le (step S20). If so, the extracted Pro processor, the PI data (step S21) and then checks whether the PI extracted data with the memory <b>14</b> existing PI data match (step S22).

When it was decided in step S17 that no Empfangssta tion exists, if it is determined in step S19 that the Received signal level Vs is less than the fixed level Vth is, or was, if decided in step S22 that the do not match PI data, the processor checks whether the net result process for all single AF data in the AF list are executed (step S24). If this still is not completed, the processing flow returns to Step S13, and the above-mentioned operations are again get. If it is determined in step S22 that the PI-Da th match, the processor switches the Stummabstimm circle <b>18</b> from to end the audio muting (Step S23). is through the specified network-Follow-Up a station select which AF-frequency data from the AF possesses list, wherein the reception signal level V s is equal to or is greater than the set level V th and their from the transmission wave removed PI data with the voreingestell th PI data match.

If that the power-sequence was determined in step S24, process for all AF frequency data groups in the AF list was carried out, the processor reads again the AF-Da th the currently requested preset station from the corresponding storage area in memory <b>14</b> out (Step S25). The processor outputs the AF data to the PLL Circuit (step S26) and sets simultaneously the PL-timer (step S27). After the PLL timer with started the time output (step S28), on the Pro cessor muting <b>18</b> from to the audio Stummabstim to end flow (step S29). By this operation even if the reception state is not good enough, the requested preset station is selected, if no RDS station received signal level Vs equal to or higher than the set level V th and from the transmitting wave removed PI data with the preset PI data coincides, by the net-result operation on Because of the AF list corresponding to the requested voreinge set station can be received.

As described, in which erfindugnsgemäßen Stationenaus selection process initially started the audio muting, if the station selection command for selecting one of a Variety is output of preset stations, and the reception frequency in accordance with the AF data of the requested preset station is set, and the audio Muting is terminated when the preset Sta tion is the RDS station and its received signal level equal or is higher than the set level, and by the received transmission wave derived PI data with presets asked PI data match. If the tax is th frequency no RDS station with the same size or size rem received signal level as fixed level and with PI Data corresponding to the preset data are received, PI, gene can be, the audio muting is terminated, if the RDS station, wherein the reception signal level is equal to or is higher than the set level, and by the Transmission shaft removed PI data with the preset PI data coincide, are received, by the network-Follow-Up gene was due to the AF list corresponding to the desired preset station so that an RDS station with good Receiving condition can be selected before the audio Stum mabstimmen is terminated.

This is the sense of incompatibility when choosing the preset station securely prevented by the the generation of noise can be caused as it in conventional devices is the case. When requested before set station can not be received, the RDS station with the same PI data as requested receiving station.

<b>Fig.</b> 4

part 4A

S1: Audio MuteS2: Enter data from preset station to PLLS3: Set PLL timerS4: Expired?S5: Is it an RDS broadcast?S6: call reception signal level V_s fromS7: it is at least equal to the value?S8: Set PI-timerS9: Enter PI datesS10: Expired?S11: Votes PI data agree?S12: Complete Audio Mute

part 4B

S13: Lies AF data from memoryS14: Give AF data to PLLS15: Set PLL timerS16: Expired?S17: station detection signal available?S18: call reception signal level V_s fromS19: it is at least equal to the value?S20: Is it an RDS broadcast?S21: Give a PI dataS22: Votes PI data agree?S23: Complete Audio MuteS24: process for entire AL-list completed?S25: Lies AF data of preset stationS26: Give AF data to PLLS27: Set PLL timerS28: Expired?S29: Complete Audio Mute

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