Some standard content:
ICS_33.160
National Standard of the People's Republic of China
GB/T15770—1995
Technical Specification of the Radio Data System
Specification of the radio data system1995-12-08
State Administration of Technical Supervision
1996-08-01Implementation
GB/T15770—1995
This standard is formulated with reference to the "Specification of Radio Data System" (EN50067:1992) published by the European Committee for Electrotechnical Standardization (CENELEC), and is equivalent to the standard in terms of technical content. At the same time, reference is made to the EBU3244 document (1984) and the American RBDS standard (1993).
The principle followed in formulating this standard is to keep as close to international standards as possible, while taking into account the specific domestic conditions, and strive to achieve scientific, reasonable, practical and feasible. The main parameters of RDS: data structure, encoding and decoding method, data protection, and application method are all in accordance with the European standard form. Taking into account the specific situation in my country, some parts have been supplemented and modified, such as: program identification (PI) code, Chinese character encoding character set, program type (PTY) code, etc.
According to the requirements of the format specified by the national standard, two chapters have been added: Chapter 1 Scope, Chapter 2 Reference Standards, Chapter 4 of the original European standard has been changed to Chapter 3 Terms, and the original Chapters 1, 2, and 3 have been changed to Chapters 4, 5, and 6 respectively. The article numbers and contents in each chapter remain unchanged or slightly changed. Appendix A and Appendix B of this standard are the appendices of the standard. Appendix C, Appendix D, Appendix E, Appendix F, Appendix G, and Appendix H of this standard are the appendices for reminders. This standard was proposed by the Ministry of Radio, Film and Television. This standard is technically managed by the Standardization Planning Institute of the Ministry of Radio, Film and Television. The drafting units of this standard are: Radio Science Research Institute of the Ministry of Radio, Film and Television, Guangdong Provincial Radio and Television Bureau. The main drafters of this standard are: Zhou Jiyu, Rong Mingliang, Kong Xiaofang, and Bai Yong. I
1 Scope
National Standard of the People's Republic of China
Technical Specification of the Radio Data System (RDS)
Specification of the radio data systemGB/T15770—1995
This standard specifies the modulation characteristics, baseband coding, message format, addressing and coding and related protocols of the Radio Data System (RDS).
This standard applies to the transmission, reception, testing and development of RDS signals for 87.0MHz~108.0MHz FM sound broadcasting in my country.
2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB1988—89 Information processing Seven-bit coded character set for information exchange GB2311—90
Information processing Seven-bit and eight-bit coded character set code expansion technology GB2312—80 Chinese character coded character set for information exchange Basic set FM broadcasting mono
GB4311.1—84
GB 4311.2—84
GB 8565.2—88
3 Terminologywww.bzxz.net
FM broadcasting stereo
Information processing Coded character set for text communication Part 2: Graphic character set 3.1 Program Identification (PI) ProgramIdentification is a code message that enables the receiver to distinguish different countries and regions transmitting the same program. Its important application is that when the program tuned to by the receiver is not well received, this message can be used to enable the receiver to automatically search for an alternative frequency. Its encoding method is shown in Appendix A. 3.2 Program Service Name (PS) Program Service name is a text of no more than 4 double-byte or 8 single-byte characters. RDS receivers with this function can display the program service name of the station being listened to. Its encoding method is shown in Appendix B. 3.3 Program Type (PTY) Program Type is a program type identification code, which is transmitted with each program column and indicates which category of the 31 programs the program being broadcast belongs to. The receiver receives and records this type of program according to this identification code. Its encoding method is shown in Appendix C. 3.4 Traffic Festival Identification (TP) Traffic-Program identification is a switch signal, which indicates whether the program service being listened to is broadcasting a traffic announcement program through the corresponding indicator light on the receiver.
3.5 Traffic Announcement Identification (TA) Traffic-Announcement identification is a switching signal, indicating whether a traffic announcement is being broadcast. The receiver uses this signal to automatically switch to the program with traffic announcements, and returns to the original working state after the traffic announcement is broadcast. Approved by the State Administration of Technical Supervision on December 8, 1995, and implemented on August 1, 1996
GB/T15770—1995
3.6 Alternative Frequency Table (AF) list of Alternative Frequencies The AF table gives information about transmitters that broadcast the same program in the same or adjacent receiving areas. The receiver stores this table to reduce the time of searching for alternative frequencies. This is particularly useful for mobile reception. 3.7 Decoder Identification (DI) Decoder Identification is a switching signal that indicates which of the 16 operating modes (or a combination thereof) the broadcast program uses. 3.8 Music/Speech Switch (M/S) Music/Speech switch is a two-state signal that indicates whether a music or speech program is being broadcast. The listener adjusts the receiver volume based on this signal to achieve the best effect.
3.9 Program Item Number (PIN) Program-Item Number is the scheduled program start date and time announced by the radio station. The receiver uses this signal to select the program to be pre-listened. 3.10 Radiotext (RT) Radiotext
A character string encoded according to Appendix B that can be displayed on a receiver equipped with a display screen. 3.11 Enhanced Other Network Information (EON) Enhanced Other Network information This information is used to update the PI, PIN, PTY, TP, TA and AF information of other program services other than the tuned program service. Receivers with EON function can listen to tuned programs and traffic announcements of other programs that refer to each other through the EON function. 3.12 Transparent Data Channel (TDC) Transparent Data Channel is a data channel with 32 sub-channels. These channels are used to transmit single-byte graphic characters or double-byte graphic characters (including spliced graphics), or computer programs and similar non-display data. 3.13 In-House application (IH) In-House application Data encoded only within the broadcasting organization. Its use can be determined by each broadcasting organization. 3.14 Time and Date (CT) Clock-Timeanddate is the broadcast time and date code. According to regulations, the Universal Coordinated Time (UTC) and the Minimum Julian Day (MJD) should be used. The listeners do not use this information directly. The conversion into local time and date is implemented in the receiver. The encoding method is shown in Appendix D. 3.15 Radio Paging (RP) RadioPaging uses the existing FM broadcasting system as the transmission system for broadcast paging. 3.16 Emergency Warning System (EWS) EmergencyWarningSystems is used to provide emergency situations. The receiver can automatically tune and identify this information. 3.17 Traffic Message Channel (TMC) Traffic Message Channel is used to transmit coded traffic information. The encoding format is to be determined. 3.18 Positioning and Navigation (LN) LocationandNavigation This feature provides information about the location of the transmitter and provides data for navigation and positioning. 4 Modulation characteristics of data channels (physical layer) This broadcast data system is used for 87.0~108.0MHz stereo (pilot system) or mono FM sound broadcasting. Broadcast data receivers should not be interfered by signals other than the data channel. The data signal is modulated and transmitted on a subcarrier. After being mixed with a stereo composite signal (or mono signal), it is sent to the modulation signal input terminal of the FM transmitter.
The block diagrams of the RDS transmitter equipment and a typical receiver decoder are shown in Figures 1 and 2 respectively. 2
Wide-end efficiency index
1187,5H,Choose network time piece
To produce total x
1 from VHF/FML Figure 1 Block diagram of encoder at transmitter 4.1 Subcarrier frequency Figure 2 Block diagram of typical receiver decoder Output frequency FHF/FM subcarrier frequency is 57kHz with a tolerance of ±6Hz. In stereo broadcasting, the subcarrier frequency is locked to the third harmonic of the 19kHz pilot frequency.
4.2 Subcarrier Phase
In stereo broadcasting, the subcarrier frequency is locked in phase with the third harmonic of the 19kHz pilot. The tolerance of its phase angle is ±10 at the FM radio modulation signal input.
4.3 Subcarrier Level
GB/T15770—1995
The nominal frequency deviation of the unmodulated subcarrier to the FM main carrier is ±1.0kHz~±7.5kHz, and the recommended value is ±2.0kHz. It is recommended that a margin should be left in the decoder and demodulator to allow a full frequency deviation of ±7.5kHz. 4.4 Modulation Method
The data source is subjected to suppressed carrier amplitude modulation on the subcarrier after bi-phase encoding and shaping. It can be regarded as a variation of bi-phase phase shift keying (PSK) with a phase offset of ±90°.
4.5 Data rate and clock frequency
The basic data rate of RDS is 1187.5bit/s±0.125bit/s. The clock frequency is 1187.5Hz, obtained by dividing the 57kHz subcarrier frequency by 48 times.
4.6 Differential encoding
The data source at the transmitting end is differentially encoded according to the rules in Table 1: Table 1
Previous output
(at t-time)
New input
(at t-time)
New output
(at t-time)
t: is any time, ti-1 is the time of the clock cycle of the previous information data, and the clock frequency is 1187.5Hz. When the input data level is 0, the output keeps the previous bit state unchanged, and when the input is 1, the new output bit is the complement of the previous bit. The receiver uses the opposite process to decode. See Table 2: Table 2
Previous input
(at - time)
4.7 Data channel spectrum shaping
New input
(at t time)
New output
(at time)
Since each data source is encoded as a bi-phase code, the energy of the data signal at and near the subcarrier frequency 57kHz is minimized, thereby avoiding the data signal from causing crosstalk in the phase-locked loop stereo decoder. The bi-phase code formation process is shown in Figure 1. Each data bit generates a single pulse pair e(t). That is:
A logic "1" data bit is generated:
e(t)=s(t)—s(t-ta/2)
A logic "0" data bit is generated:
e(t)=—8(t)+(t—ta/2)
These pulse pairs are shaped by an H(f) filter to achieve the required limited bandwidth spectrum: Hr(f)=
fcosfta
0≤f≤2/ta
f>2/ta
·（1）
·（3）
Where: ta=1187.5s
GB/T15770—1995
In order to make the broadcast data system have the best performance in resisting random interference, the data spectrum shaping filter should be equally shared between the transmitter and the receiver. Therefore, ideally, the receiver's data filtering should be the same as the transmitter's, as shown in the above formula (3). The total data channel frequency response characteristic H(f) is then 100% cosine roll-off. The transmitter and receiver low-pass filter frequency response characteristics, determined by formula (3), are shown in Figure 3a. The total data channel frequency response characteristics are shown in Figure 3b.
192(1
. Hs
The frequency response characteristics of the transmitter or receiver data shaping filter are 1920
4, Hz
Figure 3b Synthetic frequency response characteristics of transmitter and receiver data shaping filters The spectrum of the transmitted bi-phase code broadcast data signal is shown in Figure 4a, and the time function of a single bi-phase code (at the time of transmission) is shown in Figure 4b. 5
GB/T15770—1995
The waveform of the 57kHz broadcast data signal at the output of the broadcast data source encoder is shown in Figure 4c. 0.5
24024-0
Figure 4a Spectrum of the bidirectional code of the broadcast data signal +.a
When hot||tt ||Figure 4b Single biphase code time function
Beijing time
One-point display number starts at 0 time
One-point,
Figure 4c Broadcast data signal
5 Baseband coding (data link layer)
5.1 Baseband coding structure
GB/T15770—1995
Figure 5 is the structure of baseband coding. The largest unit in the structure is called "group", which contains 104 bits. Each group contains 4 blocks of 26 bits each. Each block contains 16-bit information words and 10-bit check words. 1 group 1 system = 114 bits
16 bits
signal
1 Block = 26 bits
mmu]ma[m.maJm./m,msna/mm,m,mg Figure 5
5.2 Bit transmission order
Structure of baseband coding
Compared with the
, binary numbers or binary address values, the high bit is transmitted first (see Figure 6). Therefore, the last transmitted bit is all information words, check words,
level 2°.
Data transmission is completely synchronous, and there is no gap between each data group and data block. Group = bit.
1 The chip in the group is sent first and is selected as
High significant bit
4 chip special code
Low significant bit
1-B version
Figure 6 Message format and address
H setting C =A weak
sick heart·white
medium quantity should be
where: group code = 4 bits; version code Bo = 1 bit; PI code = 16 bits; TP code = 1 bit, PTY = 5 bits. Check word + offset word = 10 bits, providing error check and block and group synchronization for the message.6 Differential encoding
The data source at the transmitting end is differentially encoded according to the rules in Table 1: Table 1
Previous output
(at t-time)
New input
(at t-time)
New output
(at t-time)
t: is any time, ti-1 is the time of the clock cycle of the previous information data, and the clock frequency is 1187.5Hz. When the input data level is 0, the output keeps the previous bit state unchanged, and when the input is 1, the new output bit is the complement of the previous bit. The receiver uses the opposite process to decode. See Table 2: Table 2
Previous input
(at - time)
4.7 Data channel spectrum shaping
New input
(at t time)
New output
(at time)
Since each data source is encoded as a bi-phase code, the energy of the data signal at and near the subcarrier frequency 57kHz is minimized, thereby avoiding the data signal from causing crosstalk in the phase-locked loop stereo decoder. The bi-phase code formation process is shown in Figure 1. Each data bit generates a single pulse pair e(t). That is:
A logic "1" data bit is generated:
e(t)=s(t)—s(t-ta/2)
A logic "0" data bit is generated:
e(t)=—8(t)+(t—ta/2)
These pulse pairs are shaped by an H(f) filter to achieve the required limited bandwidth spectrum: Hr(f)=
fcosfta
0≤f≤2/ta
f>2/ta
·（1）
·（3）
Where: ta=1187.5s
GB/T15770—1995
In order to make the broadcast data system have the best performance in resisting random interference, the data spectrum shaping filter should be equally shared between the transmitter and the receiver. Therefore, ideally, the receiver's data filtering should be the same as the transmitter's, as shown in the above formula (3). The total data channel frequency response characteristic H(f) is then 100% cosine roll-off. The transmitter and receiver low-pass filter frequency response characteristics, determined by formula (3), are shown in Figure 3a. The total data channel frequency response characteristics are shown in Figure 3b.
192(1
. Hs
The frequency response characteristics of the transmitter or receiver data shaping filter are 1920
4, Hz
Figure 3b Synthetic frequency response characteristics of transmitter and receiver data shaping filters The spectrum of the transmitted bi-phase code broadcast data signal is shown in Figure 4a, and the time function of a single bi-phase code (at the time of transmission) is shown in Figure 4b. 5
GB/T15770—1995
The waveform of the 57kHz broadcast data signal at the output of the broadcast data source encoder is shown in Figure 4c. 0.5
24024-0
Figure 4a Spectrum of the bidirectional code of the broadcast data signal +.a
When hot||tt ||Figure 4b Single biphase code time function
Beijing time
One-point display number starts at 0 time
One-point,
Figure 4c Broadcast data signal
5 Baseband coding (data link layer)
5.1 Baseband coding structure
GB/T15770—1995
Figure 5 is the structure of baseband coding. The largest unit in the structure is called "group", which contains 104 bits. Each group contains 4 blocks of 26 bits each. Each block contains 16-bit information words and 10-bit check words. 1 group 1 system = 114 bits
16 bits
signal
1 Block = 26 bits
mmu]ma[m.maJm./m,msna/mm,m,mg Figure 5
5.2 Bit transmission order
Structure of baseband coding
Compared with the
, binary numbers or binary address values, the high bit is transmitted first (see Figure 6). Therefore, the last transmitted bit is all information words, check words,
level 2°.
Data transmission is completely synchronous, and there is no gap between each data group and data block. Group = bit.
1 The chip in the group is sent first and is selected as
High significant bit
4 chip special code
Low significant bit
1-B version
Figure 6 Message format and address
H setting C =A weak
sick heart·white
medium quantity should be
where: group code = 4 bits; version code Bo = 1 bit; PI code = 16 bits; TP code = 1 bit, PTY = 5 bits. Check word + offset word = 10 bits, providing error check and block and group synchronization for the message.6 Differential encoding
The data source at the transmitting end is differentially encoded according to the rules in Table 1: Table 1
Previous output
(at t-time)
New input
(at t-time)
New output
(at t-time)
t: is any time, ti-1 is the time of the clock cycle of the previous information data, and the clock frequency is 1187.5Hz. When the input data level is 0, the output keeps the previous bit state unchanged, and when the input is 1, the new output bit is the complement of the previous bit. The receiver uses the opposite process to decode. See Table 2: Table 2
Previous input
(at - time)
4.7 Data channel spectrum shaping
New input
(at t time)
New output
(at time)
Since each data source is encoded as a bi-phase code, the energy of the data signal at and near the subcarrier frequency 57kHz is minimized, thereby avoiding the data signal from causing crosstalk in the phase-locked loop stereo decoder. The bi-phase code formation process is shown in Figure 1. Each data bit generates a single pulse pair e(t). That is:
A logic "1" data bit is generated:
e(t)=s(t)—s(t-ta/2)
A logic "0" data bit is generated:
e(t)=—8(t)+(t—ta/2)
These pulse pairs are shaped by an H(f) filter to achieve the required limited bandwidth spectrum: Hr(f)=
fcosfta
0≤f≤2/ta
f>2/ta
·（1）
·（3）
Where: ta=1187.5s
GB/T15770—1995
In order to make the broadcast data system have the best performance in resisting random interference, the data spectrum shaping filter should be equally shared between the transmitter and the receiver. Therefore, ideally, the receiver's data filtering should be the same as the transmitter's, as shown in the above formula (3). The total data channel frequency response characteristic H(f) is then 100% cosine roll-off. The transmitter and receiver low-pass filter frequency response characteristics, determined by formula (3), are shown in Figure 3a. The total data channel frequency response characteristics are shown in Figure 3b.
192(1
. Hs
The frequency response characteristics of the transmitter or receiver data shaping filter are 1920
4, Hz
Figure 3b Synthetic frequency response characteristics of transmitter and receiver data shaping filters The spectrum of the transmitted bi-phase code broadcast data signal is shown in Figure 4a, and the time function of a single bi-phase code (at the time of transmission) is shown in Figure 4b. 5
GB/T15770—1995
The waveform of the 57kHz broadcast data signal at the output of the broadcast data source encoder is shown in Figure 4c. 0.5
24024-0
Figure 4a Spectrum of the bidirectional code of the broadcast data signal +.a
When hot||tt ||Figure 4b Single biphase code time function
Beijing time
One-point display number starts at 0 time
One-point,
Figure 4c Broadcast data signal
5 Baseband coding (data link layer)
5.1 Baseband coding structure
GB/T15770—1995
Figure 5 is the structure of baseband coding. The largest unit in the structure is called "group", which contains 104 bits. Each group contains 4 blocks of 26 bits each. Each block contains 16-bit information words and 10-bit check words. 1 group 1 system = 114 bits
16 bits
signal
1 Block = 26 bits
mmu]ma[m.maJm./m,msna/mm,m,mg Figure 5
5.2 Bit transmission order
Structure of baseband coding
Compared with the
, binary numbers or binary address values, the high bit is transmitted first (see Figure 6). Therefore, the last transmitted bit is all information words, check words,
level 2°.
Data transmission is completely synchronous, and there is no gap between each data group and data block. Group = bit.
1 The chip in the group is sent first and is selected as
High significant bit
4 chip special code
Low significant bit
1-B version
Figure 6 Message format and address
H setting C =A weak
sick heart·white
medium quantity should be
where: group code = 4 bits; version code Bo = 1 bit; PI code = 16 bits; TP code = 1 bit, PTY = 5 bits. Check word + offset word = 10 bits, providing error check and block and group synchronization for the message.2-bit transmission order
The structure of baseband coding
is that the high bit is transmitted first in the binary number or binary address value (see Figure 6). Therefore, the last transmitted bit has all the information words, check words, and
levels.
Data transmission is completely synchronous, and there is no gap between each data group and data block. = 1.
1. The middle chip of the group is sent first.
High effective bit
4. Special chip type code
Low effective bit
1-B version
Figure 6. Message format and address
H set C = A weak
sick heart·white version
middle quantity should be
where: group type code = 4 bits; version code Bo = 1 bit; PI code = 16 bits; TP code = 1 bit, PTY = 5 bits. Check word + offset word = 10 bits, providing error check and block and group synchronization for the message.2-bit transmission order
The structure of baseband coding
is that the high bit is transmitted first in the binary number or binary address value (see Figure 6). Therefore, the last transmitted bit has all the information words, check words, and
levels.
Data transmission is completely synchronous, and there is no gap between each data group and data block. = 1.
1. The middle chip of the group is sent first
high effective bit
4. The special type code
low effective
1-B version
Figure 6. Message format and address
H set C = A weak
sick heart·white version
middle quantity should be
where: group type code = 4 bits; version code Bo = 1 bit; PI code = 16 bits; TP code = 1 bit, PTY = 5 bits. Check word + offset word = 10 bits, providing error check and block and group synchronization for the message.
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