Co je zvukový výstup SPDIF (u mý zvukovky Realtek)? Co ta zkratka znamená (stačí anglicky)?
Tuším, že to bude nespojitý audiosignál (něco jako PWM), ale nevím to jistě.
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Jó, mimochodem, budu ve volným čase pracovat na tom PWM zesilovači, o kterém jste mi nedávno psali, že to prostě nejde snadno realizovat. Prostě to musí jít!!!
Takže až se to za ňákej ten pátek objeví v uploadu, tak se nedivte!!!
SPDIF
Moderátor: Moderátoři
Na nete si nehladal, vsak 
S/PDIF or S/P-DIF stands for Sony/Philips Digital Interface Format, also IEC 958 type II, part of IEC-60958. It is a collection of hardware and low-level protocol specifications for carrying PCM stereo digital audio signals between devices and stereo components.
Applications
S/PDIF is primarily used with CD players (and DVD players playing CDs), but has become common on other audio components like MiniDiscs and modern computer audio cards. It is also popular in car audio, where a large amount of wiring can be replaced with a single fiber optic cable, which is immune to electrical noise.
Another common use for the S/PDIF interface is to carry compressed digital audio as defined by the standard IEC 61937. This mode is used to connect the output of a DVD player to a home theater receiver that supports Dolby Digital or DTS surround sound.
S/PDIF is a consumer version of the standard known as AES/EBU; it provides small differences in the protocol and requires less expensive hardware.
The "S/PDIF" specifications allow several different types of cables and connectors which must match the device being used. Key words for the electrical type are "coaxial" and "RCA jack." The other type is called "optical" with the word "TOSLINK" often used, or less-often, EIAJ Optical. Adaptors do exist to convert the coaxial RCA Jack S/PDIF to the optical TOSLINK S/PDIF and vice versa (though most individual adaptors are one-way only). All require some sort of external power supply. The "optical" version is advantageous for applications where electrical noise or many wires are an issue such as car audio.
S/PDIF was developed from a standard used in the professional audio field, known as AES/EBU which is commonly used in Digital Audio Tape (DAT) systems and for transmissions in professional studio recording. S/PDIF remained identical at the protocol level, but changed the physical connectors from XLR to either electrical coaxial RCA jacks or optical TOSLINK, both of which cost less and are easier to use. The cable was also changed from 110 Ω (ohms) impedance balanced twisted pair to the already far more common (and therefore compatible and inexpensive) 75 Ω coaxial cable, using RCA jacks instead of the "BNC" connector found in broadcast television. S/PDIF is, for all intents, a consumer version of the AES/EBU format.
Main differences between AES / EBU and SPDIF
AES/EBU SPDIF
Cabling 110 ohm shielded TP or 75 ohm coaxial 75 ohm coaxial or fiber
Connector 3-pin XLR, 25-Pin D-subminiature, BNC RCA, BNC, or Toslink
Signal level 3 to 10 V 0.5 to 1 V
Modulation Biphase Mark Code Biphase Mark Code
Subcode information ASCII ID text SCMS copy protection info
Max. Resolution 24 bits 20 bits (24 bit optional)
Protocol specifications
S/PDIF is used to transmit digital signals of a number of formats, the most common being the 48 kHz sample rate format used in DAT, and the 44.1 kHz format used in CD audio. In order to support both systems, as well as others that might be needed, the format has no defined data rate. Instead the data is sent using Biphase Mark Code, which has either one or two transitions for every bit, allowing the original word clock to be extracted from the signal itself.
S/PDIF is meant to be used for transmitting 20 bit audio data streams plus other related information. To transmit sources with less than 20 bits of sample accuracy, the superfluous bits will be set to zero. S/PDIF can also transport 24 bit samples by way of four extra bits, but not all equipment supports this, and might ignore these extra bits.
Since the low-level protocol is almost the same, it is described in the AES/EBU article. The only difference is in the "Channel status bit".
The channel status bit in the S/PDIF
There is one channel status bit in each subframe, making a 192 bits word each audio block. This means that there are 192/8 = 24 bytes available each audio block. The meaning of the channel status bit is completely different between AES/EBU and the S/PDIF.
For S/PDIF, the 192 bit word is divided in 12 words of 16 bits each. The first 6 bits of the first word are a control code; the meaning of its bits are shown in detail in the following table:
Meaning of the control word in SPDIF
bit num. if not set means: if set means:
0 consumer professional
1 normal compressed data
2 copy prohibit copy permit
3 2 channels 4 channels
4 - -
5no pre-emphasis pre-emphasis
S/PDIF or S/P-DIF stands for Sony/Philips Digital Interface Format, also IEC 958 type II, part of IEC-60958. It is a collection of hardware and low-level protocol specifications for carrying PCM stereo digital audio signals between devices and stereo components.
Applications
S/PDIF is primarily used with CD players (and DVD players playing CDs), but has become common on other audio components like MiniDiscs and modern computer audio cards. It is also popular in car audio, where a large amount of wiring can be replaced with a single fiber optic cable, which is immune to electrical noise.
Another common use for the S/PDIF interface is to carry compressed digital audio as defined by the standard IEC 61937. This mode is used to connect the output of a DVD player to a home theater receiver that supports Dolby Digital or DTS surround sound.
S/PDIF is a consumer version of the standard known as AES/EBU; it provides small differences in the protocol and requires less expensive hardware.
The "S/PDIF" specifications allow several different types of cables and connectors which must match the device being used. Key words for the electrical type are "coaxial" and "RCA jack." The other type is called "optical" with the word "TOSLINK" often used, or less-often, EIAJ Optical. Adaptors do exist to convert the coaxial RCA Jack S/PDIF to the optical TOSLINK S/PDIF and vice versa (though most individual adaptors are one-way only). All require some sort of external power supply. The "optical" version is advantageous for applications where electrical noise or many wires are an issue such as car audio.
S/PDIF was developed from a standard used in the professional audio field, known as AES/EBU which is commonly used in Digital Audio Tape (DAT) systems and for transmissions in professional studio recording. S/PDIF remained identical at the protocol level, but changed the physical connectors from XLR to either electrical coaxial RCA jacks or optical TOSLINK, both of which cost less and are easier to use. The cable was also changed from 110 Ω (ohms) impedance balanced twisted pair to the already far more common (and therefore compatible and inexpensive) 75 Ω coaxial cable, using RCA jacks instead of the "BNC" connector found in broadcast television. S/PDIF is, for all intents, a consumer version of the AES/EBU format.
Main differences between AES / EBU and SPDIF
AES/EBU SPDIF
Cabling 110 ohm shielded TP or 75 ohm coaxial 75 ohm coaxial or fiber
Connector 3-pin XLR, 25-Pin D-subminiature, BNC RCA, BNC, or Toslink
Signal level 3 to 10 V 0.5 to 1 V
Modulation Biphase Mark Code Biphase Mark Code
Subcode information ASCII ID text SCMS copy protection info
Max. Resolution 24 bits 20 bits (24 bit optional)
Protocol specifications
S/PDIF is used to transmit digital signals of a number of formats, the most common being the 48 kHz sample rate format used in DAT, and the 44.1 kHz format used in CD audio. In order to support both systems, as well as others that might be needed, the format has no defined data rate. Instead the data is sent using Biphase Mark Code, which has either one or two transitions for every bit, allowing the original word clock to be extracted from the signal itself.
S/PDIF is meant to be used for transmitting 20 bit audio data streams plus other related information. To transmit sources with less than 20 bits of sample accuracy, the superfluous bits will be set to zero. S/PDIF can also transport 24 bit samples by way of four extra bits, but not all equipment supports this, and might ignore these extra bits.
Since the low-level protocol is almost the same, it is described in the AES/EBU article. The only difference is in the "Channel status bit".
The channel status bit in the S/PDIF
There is one channel status bit in each subframe, making a 192 bits word each audio block. This means that there are 192/8 = 24 bytes available each audio block. The meaning of the channel status bit is completely different between AES/EBU and the S/PDIF.
For S/PDIF, the 192 bit word is divided in 12 words of 16 bits each. The first 6 bits of the first word are a control code; the meaning of its bits are shown in detail in the following table:
Meaning of the control word in SPDIF
bit num. if not set means: if set means:
0 consumer professional
1 normal compressed data
2 copy prohibit copy permit
3 2 channels 4 channels
4 - -
5no pre-emphasis pre-emphasis
Mam lepsi navrh. Snaz sa ucit cudzie reci. Cim skor zacnes, tym lepsie.Ako prva uloha moze byt prave preklad tohto clanku.right13 píše:aj to prelozis?
Vobec to nemyslim ironicky,ale smrtelne vazne.Ja som sa zacal ucit anglicky ked som mal viac nez 30,no a rezvy vidim u seba stale. V dnesnej dobe sa clovek, ktory vie len cesky/slovensky sam zaraduje na druhu kolaj. Este lepsie je, ked v nasom regione okrem angliny vies co-to aj nemecky, polsky,rusky (mozno by bolo dobre aj madarsky,ale k tomu sa nevyjadim, lebo tejto reci naozaj nerozumiem
). Nuz ale toto si uz urcite pocul, nakoniec raz to tu uz tiez pisal Hill..Existuje takovej šikovnej prográmek- jmenuje se Seznam Lištička. Po jeho instalaci stačí, když na netu najedeš myší na neznámý anglický slovo a po chvilce se Ti vedle v nažloutlým rámečku objeví překlad toho slova(většinou).
Sice jsem se učil anglicky, ale je tomu už nějakej ten pátek. Dá se to stáhnout někde na Seznamu.
Sice jsem se učil anglicky, ale je tomu už nějakej ten pátek. Dá se to stáhnout někde na Seznamu.
Kdo není ve dvaceti levičák, nemá srdce,
kdo je levičák ve čtyřiceti, nemá rozum.
— Winston Churchill
kdo je levičák ve čtyřiceti, nemá rozum.
— Winston Churchill