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In daily life, each of us has listened to many songs with headphones or slightly. Do you know what the interfaces above are and the differences between different interfaces?

Today, I will introduce you to some commonly used audio interfaces. I hope you will have a new understanding of the interfaces on audio devices ~

PS: At the end of the text, you can directly view the common audio plugs and interfaces.

First of all, we will popularize the two categories of audio signal interfaces, and lay the foundation for understanding the specific interfaces next. Audio signal interface according to the type of transmission signal can be divided into analog audio interface and digital audio interface; according to the wiring method can be divided into balanced interface and unbalanced interface.

Analog Audio Interface vs. Digital Audio Interface Analog Audio Interface: Analog audio is a technology for transmitting, recording, playback, and processing sound signals in an analog state. Similar to the microphone game in daily life, the transmission of analog audio interface is intuitive and easy to implement, but it will be distorted and unstable.

Common analog audio interfaces are TRS interface, XLR Canon head, RCA Lotus head.

Digital audio interface: Digital audio is the technology of recording, storing, editing, compressing or playing sound by digital means. The transmission of digital audio signal needs to sample the analog signal first, then quantize the sampled value into different levels, and then encode the quantized different levels. One level corresponds to a group of binary digits, and finally a series of binary digits are obtained, completing the conversion from analog signal to digital signal. Therefore, the higher the sampling rate and quantization level, the higher the accuracy of analog-to-digital conversion, and the stronger the restoration ability of the signal.

Common digital audio interfaces are AES / EBU physical interfaces, S / PDIF interfaces, coaxial interfaces, and fiber optic interfaces.

Balanced and unbalanced interfaces Balanced transmission interfaces use two channels to transmit signals of the same voltage but opposite phase. The receiving equipment subtracts these two sets of signals, and the interference signal is cancelled out, thus obtaining a high-quality analog signal.

Common balanced transmission audio interface for TRS interface, XLR card head.

An unbalanced transmission interface consists of a signal line carrying signals and a ground line. Signal in the transmission process, the wire will be subject to external interference through the second amplification of the amplifier or amplifier, due to the weak anti-noise ability, so easy to output a section of noise sound.

Common unbalanced transmission audio interface for TS interface, RCA lotus head.

TRS (large three-core) is interpreted as Tip (tip), Ring (ring), Sleeve (sleeve), large three-core interface has three separated contacts, usually using a diameter of 6.35 mm plug, its advantage is wear resistance, suitable for repeated insertion. Due to the relatively high production cost, it is generally used in high-end professional audio equipment.

1/8TRS (small three-core, 3.5mm interface) is the most important sound card interface we have seen so far, most consumer sound cards (including onboard sound cards) are using this type of interface, such as connecting car AUX interface or audio device headphone interface.

TS (large two-core) has two separate contacts and transmits mono signals, most commonly used for guitar, bass, keyboard and other instruments.

XLR consists of a three-pin plug (male) and a locking device (female). Due to the locking device, XLR connection is quite secure, generally used for microphone connection sound card or slightly connection.

RAC (Lotus Head) Each RCA cable is responsible for transmitting one channel of audio signal, so transmitting stereo signals requires a pair of cables. For multi-channel systems, the same number of cables are allocated according to the actual number of channels. In daily life, we will see RCA on the desktop slightly, and students who play DJ should be familiar with it.

Note: Stereo RCA audio interface, the right channel is generally marked with red, the left channel is marked with blue or white.

AES / EBU interface A type of digital audio interface designed jointly by the American Society of Sound Recorders and the European Broadcasting Union, often found in professional AD / DA decoders or some high-end monitor slightly. Balanced transmission mode (digital XLR connector is generally applied) or unbalanced transmission mode (BNC connector is generally applied) can be adopted. AES / EBU interface The input/output interface transmits two channels of PCM (digital audio signal), the channels are auto-timed and self-synchronized.

Note: Although the appearance of ordinary XLR (Canon Port) is almost the same as that of AES / EBU interface, it is not recommended to transmit digital signals. AES / EBU digital Canon cable with impedance of 100 Ω is required to connect the front and rear equipment.

S / PDIF (Sony and Philips Digital Interface) is a civilian digital audio interface protocol jointly developed by Sony and Philips. Each separate interface can transmit two channels of PCM digital audio signals, so there is no interference that degrades audio quality like analog signals.

Note: Coaxial digital interface and optical fiber interface belong to the category of S / PDIF interface.

Digital coaxial interface (Digital Coaxial) is a digital audio interface belonging to the S / PDIF protocol, generally divided into RCA coaxial interface and BNC coaxial interface, often appearing in digital mixers, jukeboxes, televisions and broadcasting equipment.

(S / PDIF-RCA coaxial connector and plug)

(BNC coaxial connector and plug)

Optical fiber interface (TOSLINK / Toshiba Link) transmits digital signals in the form of optical pulses, often identified by OPTICAL, also using S / PDIF protocol, characterized by high bandwidth and low signal attenuation, used for conventional sound cards, home set-top boxes or digital TVs, connecting DVD players and AV amplifiers, supporting PCM digital audio signals, Dolby and DTS audio signals. In addition, the fiber optic interface can also use ADAT protocol.

Note: Do not bend in use, otherwise it will cut off the transmission of optical signals in the same way.

MIDI interface is usually used to connect recording equipment and computers, signal, intensity, delay pedal and other information transmitted to the computer, applied to composition, recording, writing and other scenes.

Common audio plugs and interfaces

If a musical note can trigger a deep emotional resonance, then the audio interface is the fulcrum. This article ends here, have you learned? In addition to these more common audio interface types, there are other types of audio interfaces, standards and protocols, due to space constraints, this article will not introduce one by one.

This article comes from Weixin Official Accounts: ZTE Document (ID: ztedoc)

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