What Is an Optical Audio Cable?

Video cable, referred to as video cable, is composed of two parts: video cable and connector. Among them: video cable is a coaxial shielded cable with a characteristic impedance of 75 (Euro). Common specifications are divided into 3 and 5 according to the wire diameter. There are two types of single-core and multi-core wires according to the core wire. The common specifications of the connector are divided into two types according to the connection method of the cable end: crimp joints and welding heads. According to the connection method of the equipment end, they are divided into BNC (commonly known as card head). ), RCA (commonly known as lotus head) two. Audio cable, referred to as audio cable, is composed of audio cable and connector. Among them: audio cable is generally a two-core shielded cable. Common connectors include RCA (commonly known as lotus head), XLR (commonly known as XLR), and TRS. JACKS (commonly known as pen insertion).

AV cable

The video cable is an important part of the video system in the television broadcast control room. The quality of the production directly affects the technical specifications of the video channel. Poor quality video cables may cause the signal to be reversed, the signal to be seriously attenuated, the equipment to be out of synchronization, and even the signal to be interrupted. Except for a small number of control signal lines in the video system, signals such as program signals, synchronization signals, and keying signals are transmitted by the video line. Therefore, problems with the video line are one of the common fault sources that cause equipment and system failures.

In the process of making a video cable, you must first select the correct video cable and connector. When choosing a cable, you should first pay attention to its nominal impedance. A cable with a characteristic impedance of 50 is very similar to the video cable in appearance and must not be confused. In addition, pay attention to whether the cable or connector has been oxidized. The cable or connector should be discarded or disposed of as appropriate. Otherwise, the oxide will cause solder joints to be soldered, causing serious signal attenuation or even interruption. Some manufacturers in the market cut corners and cut materials. The video cables produced do not meet the specifications, such as thin shielding layers and non-standard cable diameters. Pay attention when purchasing. In the selection of the connector, try to meet the needs of the equipment and avoid the use of a conversion head. The specifications should be used according to the specifications of the cable.

Secondly, good crimp quality or welding quality must be guaranteed. The connector using the crimping method has strict requirements on the cable diameter and crimping process of each layer of the cable. It is easier to fabricate on the surface, but if it is not noticed, it may be spliced. If it is plugged often, the reliability is lower You should try to avoid using this type of connector. When you have to use it, it is better to crimp it and then solder it. At the same time, avoid force on the cable when plugging and unplugging. Relatively speaking, the requirements of welding type joints are lower, but it is still necessary to pay attention to the specifications of the joints are the same as those of the cable. The welding requirements are the same as those of ordinary electronic circuit boards. .

Finally, you must check for open or short circuits. Whenever you make a video cable, no matter what the connector is or how long it is, you must check it with a multimeter to make sure there is no open or short circuit.

The audio cable is more complicated than the video cable. In addition to the precautions in the above three aspects, there is also a problem of balanced and unbalanced connection.

In a broadcast control room, the number of video and audio connection lines for each signal is quite large. At the same time, because the location is very concentrated, if you do not encode each connection line, it will bring great benefits to future maintenance. Big inconvenience. The method is very simple. Before making the connector, put the line code on both ends of the video and audio cable according to the pre-programmed number. The principle of coding is simple and intuitive. Overly complex or too abstract coding is also not easy to maintain.

It is recommended to use a combination of letters and numbers. For example, VD101 represents the first output port (01) of the video (V) distributor (D) and the first unit (1). Through such a set of codes, it is explained that: 1. Signal properties: video signal; 2. Signal source: video distributor; 3 Device number: No. 1 machine; 4. Port location: No. 1 output port.

The letters can be selected from commonly used English abbreviations, Chinese pinyin or other easy-to-understand letters. The common English abbreviations are listed below for reference.

Abbreviation

V: VIDEO video

A: AUDIO audio

BB: BLACK BURST (synchronization signal)

P: PLAYER

R: RECORDER recording

D: DISTRIBUTER distributor

M: MONITOR monitor

CG: CHARACTER GENERATOR

O: OPTICAL RECEIVER optical receiver

TBC: TIME BASECORRE CTOR