TG: digital (cassete sonoro)(por)
TE: R-DAT(por)
TE: S-DAT(por)
UP (abreviatura de): digital audio tape(eng)
TE: R-DAT(por)
TE: S-DAT(por)
UP (abreviatura de): digital audio tape(eng)
Definição do conceito
[ENG] Digital Audio Tape (DAT or R-DAT) is a signal recording and playback medium developed by Sony and introduced in 1987. In appearance it is similar to a Compact Cassette, using 3.81 mm / 0.15" (commonly referred to as 4 mm) magnetic tape enclosed in a protective shell, but is roughly half the size at 73 mm × 54 mm × 10.5 mm. The recording is digital rather than analog. DAT can record at sampling rates equal to, as well as higher and lower than a CD (44.1, 48, or 32 kHz sampling rate respectively) at 16 bits quantization. If a comparable digital source is copied without returning to the analogue domain, then the DAT will produce an exact clone, unlike other digital media such as Digital Compact Cassette or non-Hi-MD MiniDisc, both of which use a lossy data reduction system. | Like most formats of videocassette, a DAT cassette may only be recorded and played in one direction, unlike an analog compact audio cassette, although many DAT recorders had the capability to record program numbers and IDs, which can be used to select an individual track like on a CD player. | Although intended as a replacement for analog audio compact cassettes, the format was never widely adopted by consumers because of its expense, as well as concerns from the music industry about unauthorized high-quality copies. The format saw moderate success in professional markets and as a computer storage medium, which was developed into the Digital Data Storage format. As Sony has ceased production of new recorders, it will become more difficult to play archived recordings in this format unless they are copied to other formats or hard drives. Meanwhile, the phenomenon of sticky-shed syndrome has been noted by some engineers involved in re-mastering archival recordings on DAT, which presents a further threat to audio held exclusively in this medium. | HISTORY : DEVELOPMENT : The technology of DAT is closely based on video recorders, using a rotating head and helical scan to record data. This prevents DATs from being physically edited in the cut-and-splice manner of analog tapes, or open-reel digital tapes like ProDigi or DASH. In 1983, a DAT meeting was established to unify the standards for recording digital audio on magnetic tape developed by each company and in 1985, two standards were created: R-DAT (Rotating Digital Audio Tape) using a rotary head and S-DAT (Stationary Digital Audio Tape) using a fixed head. The S-DAT format had a simple mechanism similar to the Compact Cassette format but was difficult to develop a fixed recording head for high-density recording while the rotating head of the R-DAT had a proven track record in VCR formats like VHS & Betamax. While R-DAT would later be known as just "DAT", there would be an S-DAT media format that would be released later in the form of the Digital Compact Cassette. Sony would later introduce another R-DAT format in the form of NT which was meant to replace the Microcassette and Mini-Cassette. | The DAT standard allows for four sampling modes: 32 kHz at 12 bits, and 32 kHz, 44.1 kHz or 48 kHz at 16 bits. Certain recorders operate outside the specification, allowing recording at 96 kHz and 24 bits (HHS). Some early machines aimed at the consumer market did not operate at 44.1 kHz when recording so they could not be used to ´clone´ a compact disc. Since each recording standard uses the same tape, the quality of the sampling has a direct relation to the duration of the recording – 32 kHz at 12 bits will allow six hours of recording onto a three-hour tape while HHS will only give 90 minutes from the same tape. Included in the signal data are subcodes to indicate the start and end of tracks or to skip a section entirely; this allows for indexing and fast seeking. Two-channel stereo recording is supported under all sampling rates and bit depths, but the R-DAT standard does support 4-channel recording at 32 kHz. | DATs are between 15 and 180 minutes in length, a 120-minute tape being 60 metres in length. DATs longer than 60 metres tend to be problematic in DAT recorders due to the thinner media. DAT machines running at 48 kHz and 44.1 kHz sample rates transport the tape at 8.15 mm/s. DAT machines running at 32 kHz sample rate transport the tape at 4.075 mm/s. | COMPUTER DATA STORAGE MEDIUM : The format was designed for audio use, but through the ISO Digital Data Storage standard was adopted for general data storage, storing from 1.3 to 80 GB on a 60 to 180 meter tape depending on the standard and compression. It is a sequential-access medium and is commonly used for backups. Due to the higher requirements for capacity and integrity in data backups, a computer-grade DAT was introduced, called DDS (Digital Data Storage). Although functionally similar to audio DATs, only a few DDS and DAT drives (in particular, those manufactured by Archive for SGI workstations)[11] are capable of reading the audio data from a DAT cassette. SGI DDS4 drives no longer have audio support; SGI removed the feature due to "lack of demand". | SOURCE: DIGITAL AUDIO TAPE. in: Wikipedia. Available at: https://en.wikipedia.org/wiki/Digital_Audio_Tape Accessed: 03 aug. 2022
=========================================
[ENG] Digital Audio Tape (DAT or R-DAT) is a signal recording and playback medium developed by Sony in the mid 1980s. In appearance it is similar to a compact audio cassette, using 4 mm magnetic tape enclosed in a protective shell, but is roughly half the size at 73 mm × 54 mm × 10.5 mm. As the name suggests, the recording is digital rather than analog. DAT has the ability to record at higher, equal or lower sampling rates than a CD (48, 44.1 or 32 kHz sampling rate respectively) at 16 bits quantization. If a digital source is copied then the DAT will produce an exact clone, unlike other digital media such as Digital Compact Cassette or non-Hi-MD MiniDisc, both of which use lossy data compression. Like most formats of videocassette, a DAT cassette may only be recorded on one side, unlike an analog compact audio cassette. | ... | R-DAT and S-DAT : For a while, the DAT format was produced in two physically incompatible formats: one with helical scanning heads, called R-DAT, and one with a stationary head block, called S-DAT. S-DAT failed to gain market share as it required more expensive technlogy in the machine, compared to the relatively simple (and much cheaper) spinning head approach of R-DAT. | R-DAT and S-DAT | For a while, the DAT format was produced in two physically incompatible formats: one with helical scanning heads, called R-DAT, and one with a stationary head block, called S-DAT. S-DAT failed to gain market share as it required more expensive technlogy in the machine, compared to the relatively simple (and much cheaper) spinning head approach of R-DAT. | Uses of DAT: Professional recording industry : | DAT was widely used in the professional audio recording industry in the 1990s, and is still used to some extent today, as the archives created in the 1990s are still widely used, although most labels have a program in place to transfer these tapes to a computer-based database. DAT was used professionally due to its lossless encoding, which allowed a master tape to be created that was more secure and did not induce yet more tape noise (hiss) onto the recording. In the correct setup, a DAT recording could be created without even having to be decoded to analogue until the final output stage, since digital multi-track recorders and digital mixing consoles could be used to create a fully digital chain. In this configuration, it is possible for the audio to remain digital from the first AD converter after the mic preamp until it is in a CD player. | DAT´s were also frequently used by radio broadcasters. For example, they were used by the BBC as an emergency broadcast that would initiate if the player detected a lack of noise continued for more than a pre-determined time. This would mean that if for any reason the broadcast from the studio stopped, the DAT would continue broadcast until normal service could be resumed. | ... | In November 2005, Sony announced that the final DAT machines would be discontinued the following month.[6] However, the DAT format still finds regular use in film and television recording, principally due to the support in some recorders for SMPTE time code synchronization, although it is slowly being superseded by modern hard disk recording equipment which offers much more flexibility and storage. In 2004, Sony introduced the Hi-MD Walkman with the ability to record in linear PCM. Hi-MD has found some favor as a disc-based DAT alternative for field recordings and general portable playback. | SOURCE : DIGITAL AUDIO TAPE. in: New World Encyclopedia. Available at: https://www.newworldencyclopedia.org/entry/Digital_Audio_Tape Accessed: 03 aug. 2022.
=========================================
