KR950003963B1 - Receiving signal control method of radio data system - Google Patents

Abstract

The five basic function of a radio data system is processed in the conventional electroeric tuner equipped to the car stereo receiver. The method comprises steps; (A) storing the RDS data and checking the block number of the data; (B) inspecting and storing the received program identification (PI) code; (C) selecting the TA or ordinary broadcasting signal by checking the group type code and TA and TP switch status; (D) checking that the current signal is for music or voice signal; (E) searching the alternative frequency according the group type and program service address code; (F) executing the error routine when the alternative frequency is not received; and (G) storing and displaying the alternative frequency.

Description

Receiving Signal Control Method of Radio Data System (RDS)

1 is a block diagram showing the entire reception of a radio data system (RDS) according to the present invention.

2 is a flowchart illustrating a method of controlling a received signal of a radio data system according to the present invention.

* Explanation of symbols for the main parts of the drawings

7: RDS selector 8: RDS band pass filter

9: RDS demodulator 10: Level adjuster

11: synchronization and error correction unit l2: RDS processing microcomputer

13: LCD driver 14: LCD indicator

l5: Function selector switch 16: Alternative frequency control circuit.

The present invention relates to a method of controlling a received signal in a radio data system (hereinafter referred to as RDS). In particular, five basic functions of RDS in which digital data is multiplexed are program recognition (PI), program service name (PS), and alternative frequency ( AF), Traffic Information Broadcasting (TA), and Traffic Program (TP) functions can be demodulated by existing electronic tuner car stereo receivers.

As is well known, RDS refers to a new digital multicasting method that provides 16 service functions such as broadcasting station identification and automatic tuning by adding digital data to an existing FM stereo broadcasting signal.

Conventional RDS receivers come in three types of hardware configurations: first, separate configuration of group synchronization and error correction, second, integration of RDS processing and indicator drive and external access, and third, group synchronization and error. It is divided into the case of integrating correction and RDS processing.

In the first case, the European Broadcasting Union (EB (u)) basically has the advantage of performing the regulations, but the required integrated circuits increase the product cost, complicated circuit configuration and disadvantages.

The second case has the advantage of simplifying the circuit configuration but lacks the possibility of further realization of the RDS function.

The third case integrates group synchronization, error correction, and RDS processing to simplify the circuit configuration and enhance the external connection.However, when the RDS function is expanded, the memory shortage of the processing microcomputer and the circuit change are prevented. Rigidity is a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of these conventional problems, and employs a 57KHZ subcarrier extraction circuit separately and processes RDS demodulation signals by a specific program in a general-purpose 8-bit one-chip microcomputer, such as PI, PS, AF, TP, It is an object of the present invention to provide a broadcasting signal control method of a radio data system that smoothly performs a TA function and flexibly meets additional service function requirements.

Hereinafter, the present invention will be described in detail by the accompanying drawings.

1 is a block diagram of an entire reception block of a radio data system (RDS) according to the present invention, and includes a VHF / FM receiver 1 and a V HF / FM receiver 1 for receiving a VHF / FM RDS composite modulated signal. A noise canceling unit (2) for removing external mixing noise from the output and the introduction noise from the vehicle ignition system, and a stereo demodulation unit (3) for performing auto selection of stereo and mono using a 19KHZ pilot signal; In the RDS receiver comprising an audio amplifier 47 for amplifying to an appropriate signal size for driving the speaker 6 and a cassette deck 5 for driving cassette tapes, the RDS switch RDS S / W is turned on. When ON), the RDS selector 7 initializes the RDS operation circuit and transmits the FM demodulated RDS composite signal to the RDS (A), and the 57KHZ subcarrier carrying digital data from radio data multiplexed on the FM stereo signal. Modulation in RDS bandpass filter 8 for passing only the RDS signal, RDS demodulator 9 for synchronously detecting and demodulating radio data modulated signals, and signals between RDS demodulator 9 and RDS synchronization and error correction circuit 11 A level adjusting circuit 10 for level matching, a synchronization and error correction unit 11 for generating radio data, a clock and a start signal in synchronization with data, and outputting them to an RDS processing computer 12 which is a one-chip microcomputer; And an RDS processing computer 12 for processing the RDS demodulation signal to perform an RDS function, and an LCD display 14 for displaying the tuned frequency, program service data, etc. in response to the output processed by the RDS processing computer 12. RDS function selection switch (l5) for controlling the LCD driver 13 for driving the controller, a traffic information broadcast selection switch (TA S / W), and a selection switch (F / DS / W) for selecting program service data or frequency. Wow, alternate frequency For the service and a request when the VHF / FM receiver (1) alternative frequency control circuit 16 for sending out the data to the electronic tuner in the frequency synthesizer.

According to the RDS reception signal control method according to the present invention related to the RDS configured as described above, when data is received in the RDS processing microcomputer 12 in the RDS system initialization state as shown in FIG. A process of designating block number selection by searching data authorization, a process of checking and storing a received program recognition code (PI) using a flag (block 1), and searching for 4 bits of a group type code (GTC) Check the group of the received data and select the traffic broadcasting and general broadcasting according to the selection of the traffic information broadcasting function switch (TA S / W) and the traffic program function switch (TP S / W). When the program is completed, the program service address code (PS AC) and the broadcasting or storing the music or voice (M / S) using a flag (Block 2), and the currently being broadcast When a list of wave numbers and alternative frequencies is received, the group type and the program service address code are searched for, and the optimal alternative frequencies are searched for and stored in the alternative frequencies. If the list of alternative frequencies is not received, an error routine is performed (block 3). And, if radio data is received, retrieve the group timecode and store the received data in memory and display it or determine whether to display the frequency determined in the process of storing the alternate frequency (block 3). Display routine is performed by the display routine, and displayed through the LCD indicator 14, and when the tuned frequency is displayed, the frequency routine processing is performed to search whether the currently broadcast frequency is AM or FM, convert it to the corresponding code, and display the same. Process (block 4).

Referring to the operation and effect of the RDS reception signal control method according to the present invention made as described above are as follows.

First, the external noise of the signal output from the VHF / FM receiver 1 and the introduced noise from the vehicle ignition apparatus are removed through the noise canceller 2 in FIG. 1, and then the stereo demodulator 3 controls the stereo noise. The pilot signal is used to perform stereo and mono auto selection.

In addition, HCC (High Cut Contro1ler) oscillator and VCO (Voltage Controlled Oscillator) oscillator stop function.

The output of the stereo demodulator 3 is properly amplified by the audio amplifier 4 composed of a preamplifier and a main amplifier to drive the speaker 6.

On the other hand, when the RDS switch (RDS S / W) is turned on, the RDS selector 7 initializes the radio data system A and outputs the FM demodulated RDS composite signal to the RDS band pass filter 8.

In this state, the RDS band pass filter 8 passes only the modulated RDS signal centered on the 57 KHZ subcarrier, which broadcasts the digital data from the radio data broadcast multiplexed on the FM stereo signal.

That is, it is a narrow band pass filter which passes the 57HKZ ± 2.4KHZ signal band from the baseband complex multiplexed signal, the FM detection output of the radio receiving the FM signal, and blocks other frequency bands.

Also, the passband has a gain of about 27 dB in order to provide an appropriate input level to the RDS demodulator 9 connected to the next stage.

In the RDS demodulator 9, if the phase of the RDS modulated signal is 0 ° at a certain zero crossing point, the phase is inverted to 180 ° at the next zero crossing point, and the PLL circuit is synchronized with the input carrier in a linear phase relationship so that the PLL is input radio data. When synchronized with the modulated signal, the radio data modulated signal is synchronously detected and demodulated at the output of the VCO oscillator and then output to the level adjustment circuit 10.

The level adjustment circuit 10 supplies current to the synchronization and error correction unit 11 to match the signal level between the RDS demodulation unit 9 and the RDS synchronization and error correction unit 11.

The synchronization and error correction unit 11 generates a start signal of radio data, clock and radio data by synchronizing the group synchronization with the block synchronization, and outputs it to the RDS processing computer 12, which is a one-chip microcomputer.

In such a state, the RDS processing microcomputer 12 processes the RDS demodulation signal for each selected block as shown in the flowchart shown in FIG. 2 to perform the RDS function. Same as

First, the RDS initializes the system to satisfy the initial conditions of the control register, the Intercept Enable Control (IE), the Stack Pointer Register (SP), and the register (PSW) containing the program status information.

Thereafter, when data is received, the RDS data is stored, and then the data is searched for the number of blocks of data to execute the routine of the corresponding block.

If block l is specified, the first block of program identification code (PI) received data is identified and stored using a flag.

Next, if block 2 is specified, the first 4 bits of the second block are searched for 4 bits of the group type code (GITC) to confirm which group the received data is.

Then, the traffic information broadcast selection switch (TA S / W) and the traffic program function switch (TP S / W) are checked to select traffic and general broadcasts. The TA switch checks whether there is traffic broadcasting in the current service. The TP switch is a switch to check whether the current service can transmit traffic.

When the selection is completed, the corresponding broadcast is displayed on the LCD display 14, and then a flag is set to indicate a program service address code (PSAC) indicating the address of the data of blocks 3 and 4, and that the broadcast is performed by music (Music or voice). Save (Speech) using the flag.

Next, if block 3 is specified, it stores a list of frequencies that are currently being broadcast and alternative frequencies, retrieves the group type code (GTC) and program service address code (PSAC), and then searches for the optimal alternative frequency (AF). Set the alternate frequency.

If the alternate frequency is not included in the alternate frequency list, the error routine is received and data is received again.

If block 4 is specified, the group type code (GTC) of the radio reception data is retrieved, the received data is stored in the memory, and it is determined whether to display or display the frequency determined in block 3. 14).

In this case, the frequency routine searches for whether AM or FM is currently being broadcast, converts it into a corresponding code, and then displays it.

The display processing routine also displays the information stored in the memory at block 3 or block 4 via the LCD indicator 14 in accordance with the data determined at block 4.

When the data error of the received substitute frequency occurs, the error processing routine determines whether an error occurs in the tuned frequency or an error in the substitute frequency list using the flag of the substitute frequency.

Subsequently, the AM frequency or FM signal is searched using the alternative frequency code, and if an error occurs in the tuned frequency, the optimum alternative frequency is found, and if an error occurs in the alternative frequency list, an appropriate alternative frequency list is set.

The control operation of the RDS processing microcomputer 12 has been described above.

The LCD driver 16 receives the output processed by the RDS processing microcomputer 12 to drive the LCD display 14 for displaying the tuned frequency, program service data, and the like.

Here, the input data is 8 bits in one fetch cycle, and the output display segment driving capability is five segments in the case of static and consists of four common terminals.

The function selection switch 15 includes an RDS switch for selecting the RDS function (RDS S / W), a switch for selecting traffic information broadcasting (TA S / W) and a traffic program function switch (TP S / W), and a frequency and program. It consists of a service data selection switch (F / DS / W).

The alternative frequency control circuit unit 16 is to send control data to the frequency synthesizer of the electronic tuner of the conventional car stereo when the service for the alternative frequency is required, and may be composed of a plurality of buffers, an inverter, and an inverter schmitt trigger.

As described above, the present invention realizes convenient and important service functions such as basic functions (PI, PS, AF, TA, and TP) of RDS by using a conventional electronic tuner car stereo receiver by a specific program of one-chip microcomputer. It is possible to improve the reliability and quality of the product.

Claims (3)

In a radio data system that performs multiple service functions by multiplexing digital data to a VHF / FM radio signal, the RDS processing microcomputer 12 stores data after receiving RDS data when the data is received in the RDS system initialization state. A process of designating block number selection by searching data authorization of a few blocks, checking and storing a received program recognition code (PI) by using a flag (block 1), and searching a group type code (GTC) Check whether the received data is the data of the group, and select the traffic broadcasting and general broadcasting according to the selection of the traffic information broadcasting function switch (TA S / W) and the traffic program function switch (TP S / W). When the selection is completed, storing the program service address code (PSAC) and whether the broadcast is music or voice (M / S) using a flag (Block 2), When a list of currently broadcasted frequencies and alternative frequencies is received, the group type and program service address code is searched for, and the optimum alternative frequencies are searched to store the alternative frequencies. If the list of alternative frequencies is not received, an error routine is performed. Process (block 3) and, if radio data is received, whether to retrieve the group type code and store the received data in memory and display it or to display the frequency determined in the process of storing the alternative frequency (block 3). Determining and finally performing a display routine to display through the LCD indicator l4, and if it is not determined whether to display, performing a frequency routine (block 4). Signal control method. The method of claim 1, wherein in the block 3 processing, the error routine process determines whether an error occurs in a frequency tuned by using a flag of a substitute frequency when a data error of a received substitute frequency occurs, or an error occurs in an alternative frequency list. A method of controlling a received signal of a radio data system (RDS), characterized in that it comprises a process of discriminating. The method of claim 1, wherein in the block 4 processing, the frequency routine processing is performed by searching for an AM or FM signal which is currently being broadcast and converting the code into a corresponding code and then displaying the same through the LCD display 14. A method for controlling a received signal of a radio data system (RDS).