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64-679: ARI was rendered obsolete by the more modern Radio Data System and the ARD stopped broadcasting ARI signals on March 1, 2005. The SK signal is actually the 57 kHz subcarrier that is transmitted by the ARI-compliant FM station for this functionality. This frequency, like the RDS subcarrier frequency is chosen because it is the third harmonic of the 19 kHz pilot tone used in the FM-stereo transmission standard. An easy way to understand that

128-421: A liquid-crystal display capable of showing images such as weather maps, accompanied by "a light pen with which the radio can be programmed from barcodes", these barcodes encoding programme information, and supported detachable modules, of which a cassette player module and a printer module were developed. Despite reluctance to develop screen-based functionality that might bring RDS into competition with television,

192-422: A "group" of 104 bits (64 data bits + 40 check bits). There are slightly over 11.4 groups transmitted per second. There is no gap between blocks. The receiver synchronizes to groups and blocks by checking CRCs on each 26 bits until synchronization is achieved. Once synchronized (the offset word is predictable), the code is capable of correcting up to 5-bit burst errors . This basic modulation and block structure

256-448: A 57  kHz subcarrier , so there are exactly 48 cycles of subcarrier during every data bit. The RBDS/RDS subcarrier was set to the third harmonic of the 19 kHz FM stereo pilot tone to minimize interference and intermodulation between the data signal, the stereo pilot and the 38 kHz DSB-SC stereo difference signal. (The stereo difference signal extends up 38 kHz + 15 kHz = 53 kHz, leaving 4 kHz for

320-442: A digital communication channel is the capacity excluding the physical layer protocol overhead, for example time division multiplex (TDM) framing bits , redundant forward error correction (FEC) codes, equalizer training symbols and other channel coding . Error-correcting codes are common especially in wireless communication systems, broadband modem standards and modern copper-based high-speed LANs. The physical layer net bitrate

384-472: A format sometimes abbreviated like "16bit / 44.1kHz". CD-DA is also stereo , using a left and right channel , so the amount of audio data per second is double that of mono, where only a single channel is used. The bit rate of PCM audio data can be calculated with the following formula: For example, the bit rate of a CD-DA recording (44.1 kHz sampling rate, 16 bits per sample and two channels) can be calculated as follows: The cumulative size of

448-424: A growing number of RDS implementations in portable audio and navigation devices thanks to lower-priced, small-footprint solutions. The RDS sub-carrier at 57 kHz occupies ±2 kHz of the composite spectrum which in theory keeps it above the upper cutoff of the stereo subcarrier at 53 kHz. However the 53 kHz cutoff is entirely dependent on the performance of the 15 kHz low pass filters used before

512-614: A length of PCM audio data (excluding a file header or other metadata ) can be calculated using the following formula: The cumulative size in bytes can be found by dividing the file size in bits by the number of bits in a byte, which is eight: Therefore, 80 minutes (4,800 seconds) of CD-DA data requires 846,720,000 bytes of storage: where MiB is mebibytes with binary prefix Mi, meaning 2 = 1,048,576. The MP3 audio format provides lossy data compression . Audio quality improves with increasing bitrate: For technical reasons (hardware/software protocols, overheads, encoding schemes, etc.)

576-518: A problem for people taking portable radios into or out of North America. The RDS standard as specified in EN 50067:1998 is separated into these sections according to the OSI model . (The network and transport layers are excluded, as this is a unidirectional broadcast standard.) The physical layer in the standard describes how the bitstream is retrieved from the radio signal. The RDS hardware first demodulates

640-668: A project of the European Broadcasting Union (EBU), but has since become an international standard of the International Electrotechnical Commission (IEC). Radio Broadcast Data System ( RBDS ) is the official name used for the U.S. version of RDS. The two standards are only slightly different, with receivers able to work with either system with only minor inconsistencies in the displayed data. Both versions carry data at 1,187.5 bits per second (about 1.2   kbit/s ) on

704-429: A receiver can quickly search for a station which includes traffic reports. Another bit, traffic announcement (TA), is sent in block types 0A, 0B and 15B to indicate that such a report is in progress. It is common for otherwise- simulcast transmitters to have periodic local traffic reports which are customized to the individual transmitter. The traffic announcement bit tells a receiver that a transmitter-specific broadcast

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768-464: A switch usually marked SDK or VF. Radios that used the "classic" mechanical push-button preset system would have one of these buttons set aside as the VF switch. If this switch was on, the radio would mute unless it was tuned into a station that transmitted this signal. If the radio was a digitally-tuned receiver, this switch usually engaged an "ARI-seek" mode which had the radio seek for any ARI station if it

832-453: Is 125 Mbit/s, due to the 4B5B (four bit over five bit) encoding. In this case, the gross bit rate is equal to the symbol rate or pulse rate of 125 megabaud, due to the NRZI line code . In communications technologies without forward error correction and other physical layer protocol overhead, there is no distinction between gross bit rate and physical layer net bit rate. For example,

896-464: Is assigned to France , Norway , Belarus and Egypt . Neighbouring countries never have the same country code which means it is not necessary for PI codes to be coordinated with adjacent countries. This is a short list of the full group type. Each group type may have a secondary version available This can be considered an additional program type bit, and indicates that the station broadcasts periodic traffic reports . By including it in every group,

960-429: Is expressed in the unit bit per second (symbol: bit/s ), often in conjunction with an SI prefix such as kilo (1 kbit/s = 1,000 bit/s), mega (1 Mbit/s = 1,000 kbit/s), giga (1 Gbit/s = 1,000 Mbit/s) or tera (1 Tbit/s = 1,000 Gbit/s). The non-standard abbreviation bps is often used to replace the standard symbol bit/s, so that, for example, 1 Mbps

1024-504: Is in progress, and it should avoid switching frequencies while they are in progress. (There is a different form of traffic announcement bit in block type 14B, which indicates the presence of a traffic announcement on a different frequency, so that radio receivers can automatically switch.) These are non-comprehensive examples that cover just the simple messages likes station name, radio text, and date/time. As we have already described previous fields above, these dot points below show just

1088-804: Is not the case for modern modulation systems used in modems and LAN equipment. For most line codes and modulation methods: More specifically, a line code (or baseband transmission scheme) representing the data using pulse-amplitude modulation with 2 N {\displaystyle 2^{N}} different voltage levels, can transfer N {\displaystyle N} bits per pulse. A digital modulation method (or passband transmission scheme) using 2 N {\displaystyle 2^{N}} different symbols, for example 2 N {\displaystyle 2^{N}} amplitudes, phases or frequencies, can transfer N {\displaystyle N} bits per symbol. This results in: An exception from

1152-408: Is possible without bit errors for a certain physical analog node-to-node communication link . The channel capacity is proportional to the analog bandwidth in hertz. This proportionality is called Hartley's law . Consequently, the net bit rate is sometimes called digital bandwidth capacity in bit/s. The term throughput , essentially the same thing as digital bandwidth consumption , denotes

1216-437: Is provided by the network equipment or protocols, we have the following relation: for a certain communication path. These are examples of physical layer net bit rates in proposed communication standard interfaces and devices: In digital multimedia, bit rate represents the amount of information, or detail, that is stored per unit of time of a recording. The bitrate depends on several factors: Generally, choices are made about

1280-528: Is that this frequency is the 19 kHz pilot tone multiplied by 3. An ARI-equipped radio would illuminate an indicator lamp to show that this function was in force. Most such radios would use this function further to help users search for ARI broadcasts. In the Radio Data System environment, the TP signal is equivalent to this basic function. The basic method implemented on an analog receiver would be

1344-405: Is the datarate measured at a reference point in the interface between the data link layer and physical layer, and may consequently include data link and higher layer overhead. In modems and wireless systems, link adaptation (automatic adaptation of the data rate and the modulation and/or error coding scheme to the signal quality) is often applied. In that context, the term peak bitrate denotes

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1408-583: Is used to mean one million bits per second. In most computing and digital communication environments, one byte per second (symbol: B/s ) corresponds to 8 bit/s. When quantifying large or small bit rates, SI prefixes (also known as metric prefixes or decimal prefixes) are used, thus: Binary prefixes are sometimes used for bit rates. The International Standard ( IEC 80000-13 ) specifies different symbols for binary and decimal (SI) prefixes (e.g., 1 KiB /s = 1024 B/s = 8192 bit/s, and 1 MiB /s = 1024 KiB/s). In digital communication systems,

1472-435: Is used, it shall be transmitted every minute according to EN 50067. The clock time group is inserted so that the minute edge will occur within ±0.1 seconds of the end of the clock time group. Time and date are packed as these: Bits per second In telecommunications and computing , bit rate ( bitrate or as a variable R ) is the number of bits that are conveyed or processed per unit of time. The bit rate

1536-410: The physical layer gross bitrate , raw bitrate , data signaling rate , gross data transfer rate or uncoded transmission rate (sometimes written as a variable R b or f b ) is the total number of physically transferred bits per second over a communication link, including useful data as well as protocol overhead. In case of serial communications , the gross bit rate is related to

1600-416: The source information rate , also known as the entropy rate . The bitrates in this section are approximately the minimum that the average listener in a typical listening or viewing environment, when using the best available compression, would perceive as not significantly worse than the reference standard. Compact Disc Digital Audio (CD-DA) uses 44,100 samples per second, each with a bit depth of 16,

1664-415: The "offset", or block number within a 4-block group. The error correction is done using a 10-bit cyclic redundancy check , with polynomial x +x +x +x +x +x +1 . (Neither a preset nor post-invert is used, as they are not necessary with a fixed-size data field.) The CRC is also summed with one of five "offset" words which identify the block: A, B, C, C′, or D. Four consecutive blocks (ABCD or ABC′D) make up

1728-440: The 57 kHz RDS subcarrier signal to extract a differential Manchester encoded signal which contains both the bit clock and the differentially encoded bitstream. This allows the RDS decoder to tolerate phase inversion of its input. At the data link layer, 26 consecutive bits form a "block", consisting of 16 data bits followed by 10 error correction bits. Four blocks make a 104-bit "group". The error correction bits also encode

1792-483: The PI code; offset C is used when the third block contains something else. Block 1 always contains the 16-bit program identifier. The first 11 bits (bits 15–5) of block 2 are also the same in all groups. The first 4 bits (bits 15–11) of block 2 are the "group type code", which describe the interpretation of the remaining data. Each group type comes "A" and "B" variants, distinguished by the fifth "B" bit (bit 10): If B=0, then

1856-462: The RBS offset words are chosen to appear as uncorrectable errors to MBS receivers.) Data within each block (and group) is transmitted most significant bit first , and thus are numbered from bit 15 (transmitted first) to bit 0 (transmitted last). The most frequently information transmitted is a 16-bit "program identification" code, identifying the transmitting radio station. Blocks A and C′ always include

1920-424: The RDS and RBDS (North American) program type (PTY) codes and their meanings: The PTY codes have undergone several expansions. The first RDS standard only defined 0–15 and 31. The later RBDS standard implemented in the U.S. assigned the same meanings to codes 0, 1 and 31, but made no attempt to match the rest of the original RDS plan and created its own list for codes 2–22 and 30, including commercially important (in

1984-399: The RDS sub-carrier because of the harmonics created by the clipping. More modern composite clippers include filtering to protect the RDS subcarrier. The RDS subcarrier typically uses 2–4 kHz of carrier deviation. Therefore, the deviation available for the program material is reduced by this amount, assuming the usual 75 kHz deviation limit is not exceeded. The following table lists

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2048-643: The U.S. National Radio Systems Committee issued the North American version of the RDS standard, called the Radio Broadcast Data System. The CENELEC standard was updated in 1992 with the addition of Traffic Message Channel and in 1998 with Open Data Applications and, in 2000, RDS was published worldwide as IEC standard 62106. The RDS-Forum (Geneva/CH) decided at its annual meeting (8–9 June 2015) in Glion/Montreux to bring

2112-540: The U.S.) radio formats such as top 40, religious, country, jazz and R&B which were not in the RDS list. This included mismatched codes for information. sport, and rock. Later RBDS standards added types 23 (College) and 29 (Weather), while the RDS type code list grew to its current size, importing some types (e.g. jazz and country) from the RDBS list. RDBS types 24–26 were added in April 2011. The code mismatches are mainly

2176-443: The above factors in order to achieve the desired trade-off between minimizing the bitrate and maximizing the quality of the material when it is played. If lossy data compression is used on audio or visual data, differences from the original signal will be introduced; if the compression is substantial, or lossy data is decompressed and recompressed, this may become noticeable in the form of compression artifacts . Whether these affect

2240-694: The above is some self-synchronizing line codes, for example Manchester coding and return-to-zero (RTZ) coding, where each bit is represented by two pulses (signal states), resulting in: A theoretical upper bound for the symbol rate in baud, symbols/s or pulses/s for a certain spectral bandwidth in hertz is given by the Nyquist law : In practice this upper bound can only be approached for line coding schemes and for so-called vestigial sideband digital modulation. Most other digital carrier-modulated schemes, for example ASK , PSK , QAM and OFDM , can be characterized as double sideband modulation, resulting in

2304-400: The achieved average useful bit rate in a computer network over a logical or physical communication link or through a network node, typically measured at a reference point above the data link layer. This implies that the throughput often excludes data link layer protocol overhead. The throughput is affected by the traffic load from the data source in question, as well as from other sources sharing

2368-498: The application specific fields. The station name and decoder identification code is sent progressively over 4 groups, where the offset is defined by bit C1 and C0. As we have already described previous fields above, these dot points below show just the application specific fields. The station name and decoder identification code is sent progressively over 4 groups, where the offset is defined by bit C1 and C0. That This Field Is For Program Identification Code When group type 4A

2432-462: The bit transmission time T b {\displaystyle T_{\text{b}}} as: The gross bit rate is related to the symbol rate or modulation rate, which is expressed in bauds or symbols per second. However, the gross bit rate and the baud value are equal only when there are only two levels per symbol, representing 0 and 1, meaning that each symbol of a data transmission system carries exactly one bit of data; for example, this

2496-501: The connection establishment phase due to adaptive modulation  – slower but more robust modulation schemes are chosen in case of poor signal-to-noise ratio . Due to data compression, the actual data transmission rate or throughput (see below) may be higher. The channel capacity , also known as the Shannon capacity, is a theoretical upper bound for the maximum net bitrate, exclusive of forward error correction coding, that

2560-503: The current zone that it was in rather than using an "SK" indicator whenever it was on an ARI station. As well, the user could control ARI search behavior based on the current zone, a user-nominated zone such as the neighboring zone or any ARI station in any zone. Blaupunkt even made attempts to roll it out into the US market since 1982 by gaining support from selected FM broadcasters in the big US cities, but it did not catch on. Besides, they were

2624-399: The encoding bit rate is the goodput that is required to avoid playback interruption. The term average bitrate is used in case of variable bitrate multimedia source coding schemes. In this context, the peak bit rate is the maximum number of bits required for any short-term block of compressed data. A theoretical lower bound for the encoding bit rate for lossless data compression is

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2688-446: The file size (in bytes) divided by the file transfer time (in seconds) and multiplied by eight. As an example, the goodput or data transfer rate of a V.92 voiceband modem is affected by the modem physical layer and data link layer protocols. It is sometimes higher than the physical layer data rate due to V.44 data compression , and sometimes lower due to bit-errors and automatic repeat request retransmissions. If no data compression

2752-516: The first 4 bits for Application/Group Type. Meaning of Block 2 Bits Block 3 is used for repeating program identification code. This allows for quick identification of radio program type, based on country, coverage area, and program reference number. While the country code is specified by the standard, bit 11 to bit 0 is specified by each country local authorities. Country codes are re-used, but only in geographically distant regions beyond FM broadcast range from each other. For example, country code F

2816-534: The following relation: In case of parallel communication , the gross bit rate is given by where n is the number of parallel channels, M i is the number of symbols or levels of the modulation in the i th channel , and T i is the symbol duration time , expressed in seconds, for the i th channel. The physical layer net bitrate , information rate , useful bit rate , payload rate , net data transfer rate , coded transmission rate , effective data rate or wire speed (informal language) of

2880-482: The gross bit rate and net bit rate is affected by the FEC code rate according to the following. The connection speed of a technology that involves forward error correction typically refers to the physical layer net bit rate in accordance with the above definition. For example, the net bitrate (and thus the "connection speed") of an IEEE 802.11a wireless network is the net bit rate of between 6 and 54 Mbit/s, while

2944-472: The gross bit rate is between 12 and 72 Mbit/s inclusive of error-correcting codes. The net bit rate of ISDN2 Basic Rate Interface (2 B-channels + 1 D-channel) of 64+64+16 = 144 kbit/s also refers to the payload data rates, while the D channel signalling rate is 16 kbit/s. The net bit rate of the Ethernet 100BASE-TX physical layer standard is 100 Mbit/s, while the gross bitrate

3008-503: The group is 0A through 15A, and contains 5+16+16 = 37 bits of data. If B=1, block 2 contains a PI code (and is encoded with offset word C′), the group is one of 0B through 15B, and contains 21 bits of data. Within Block 1 and Block 2 are structures that will always be present in both group versions, for fast and responsive identifications. The first block of every group, will always be the program identification code. The second block dedicates

3072-410: The lower sideband of the RDS signal.) The data is sent with an error correction code , but receivers may choose to use it only for error detection without correction. RDS defines many features including how private (in-house) or other undefined features can be "packaged" in unused program groups. RDS is only used on analog stations. The HD Radio equivalent is Program-associated data (PAD). RDS

3136-520: The net as well as gross bit rate of Ethernet 10BASE-T is 10 Mbit/s. Due to the Manchester line code, each bit is represented by two pulses, resulting in a pulse rate of 20 megabaud. The "connection speed" of a V.92 voiceband modem typically refers to the gross bit rate, since there is no additional error-correction code. It can be up to 56,000 bit/s downstream and 48,000 bit/s upstream . A lower bit rate may be chosen during

3200-465: The net bitrate of the fastest and least robust transmission mode, used for example when the distance is very short between sender and transmitter. Some operating systems and network equipment may detect the " connection speed " (informal language) of a network access technology or communication device, implying the current net bit rate. The term line rate in some textbooks is defined as gross bit rate, in others as net bit rate. The relationship between

3264-415: The new standard RDS2 on the way. The standard will be created in close collaboration with U.S. colleagues from NRSC RBDS-Subcommittee and should offer a unified platform for FM broadcasting and data services worldwide. The following information fields are normally contained in the RDS data: As far as implementation is concerned, most car stereos will support at least AF, EON, REG, PS and TA/TP. There are

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3328-454: The only company to put ARI-equipped sets on the U.S. marketplace, as a way of differentiating their product from others. There was talk of encouraging other manufacturers to sell ARI-equipped car radios to the U.S., but there was no action even though other manufacturers would roll out ARI-equipped radios to Germany. ARI was introduced in Toronto, Canada, around the same time as the U.S. CHFI

3392-433: The perceived quality, and if so how much, depends on the compression scheme, encoder power, the characteristics of the input data, the listener's perceptions, the listener's familiarity with artifacts, and the listening or viewing environment. The encoding bit rate of a multimedia file is its size in bytes divided by the playback time of the recording (in seconds), multiplied by eight. For real-time streaming multimedia ,

3456-425: The same network resources. See also measuring network throughput . Goodput or data transfer rate refers to the achieved average net bit rate that is delivered to the application layer , exclusive of all protocol overhead, data packets retransmissions, etc. For example, in the case of file transfer, the goodput corresponds to the achieved file transfer rate . The file transfer rate in bit/s can be calculated as

3520-420: The stereo encoder. In older equipment, these filters were only designed to protect the 19 kHz pilot and sometimes did not provide sufficient protection to the RDS subcarrier when a significant amount of stereo information was present. In this situation, stereo enhancement devices combined with aggressive audio processing could render the RDS subcarrier unreceivable. Composite clipping systems may also degrade

3584-489: The system. This was also confusing because a lot of cheaper implementations used a mechanical toggle switch to engage / disengage ARI mode and it was hard to simply use this switch simply to reset the system. This function was based on one of six tones that was in this same subcarrier and was reserved for high-end car radios. These were referred to as A, B, C, D, E and F; and they worked as a crude way of machine-based geocoding for Germany's broadcast areas. The set would indicate

3648-534: The three broadcasting partners of the EBU, the BBC were reportedly pursuing the application of RDS technology most enthusiastically and sought to attract bids from manufacturers to make a "BBC-accredited radio" supporting RDS features. Having received no manufacturer interest, however, the corporation engaged designers at Kinneir Dufort to produce a prototype showcasing these features. This prototype, unveiled in 1989, incorporated

3712-405: The utility of being able to print out information such as weather maps or even advertising was regarded as potentially interesting to both radio and television manufacturers alike. Enhancements to the alternative frequencies functionality were added to the standard and it was subsequently published as a European Committee for Electrotechnical Standardization (CENELEC) standard in 1990. In 1992

3776-631: Was inspired by the development of the Autofahrer-Rundfunk-Informationssystem (ARI) in Germany by the Institut für Rundfunktechnik (IRT) and the radio manufacturer Blaupunkt . ARI used a 57-kHz subcarrier to indicate the presence of traffic information in an FM radio broadcast. The EBU Technical Committee launched a project at its 1974 Paris meeting to develop a technology with similar purposes to ARI, but which

3840-560: Was more flexible and which would enable automated retuning of a receiver where a broadcast network transmitted the same radio programme on a number of different frequencies. The modulation system was based on that used in a Swedish paging system and the baseband coding was a new design, mainly developed by the British Broadcasting Corporation (BBC) and the IRT. The EBU issued the first RDS specification in 1984. Of

3904-605: Was originally developed for the MBS (radio paging)  [ fr ] "mobile search" protocol, with the difference that MBS (or the North American equivalent MMBS "modified MBS") does not use an offset word. To allow the two systems to interoperate (and to allow FM radio stations to transmit RBDS data while maintaining their pager contracts), the RBDS standard defines a sixth all-zero offset word E. Groups of four E blocks may be mixed with RBDS groups, and ignored by RBDS receivers. (Likewise,

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3968-461: Was out of range of the currently-tuned ARI station. This function, which is superseded by the RDS TA function, was tied in with the broadcasting studio and would be triggered whenever the traffic-announcement jingle was played. A 125 Hz tone would be modulated on the 57 kHz ARI subcarrier tone while this was happening. A radio that used a "DK" switch, often part of the "SDK" or "VF" switch,

4032-399: Was placed into "traffic-priority" mode. It would pick up on this signal and come out of a muted state or cut over a tape or CD that was playing and play the announcement at a fixed volume level. There was the ability to switch off such announcements on these sets if the driver found a particular announcement irrelevant or it ran on for too long, but it was not easily explained to people new to

4096-500: Was the station designated for such broadcasts, and ads for new Blaupunkt car stereos announced it, but just like in the U.S., ARI did not seem to catch on. Radio Data System Radio Data System ( RDS ) is a communications protocol standard for embedding small amounts of digital information in conventional FM radio broadcasts . RDS standardizes several types of information transmitted, including time , station identification and program information. The standard began as

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