Introduction to the method of connecting the shielded wire to the BNC interface

The shielded wire in the BNC connector plays a very important role in a complex environment. If it is not connected properly, not only will it be easy to skip the signal and the audio will be damaged, but there will even be no signal. Therefore, in order to ensure the stability of the transmission, the shielded wire of the BNC interface It also needs to be installed in place.

1. How to connect BNC connector with shielded wire

The following are two common connection methods of BNC shielded wires:

1. Balanced connection

The so-called balanced connection is a connection method that uses two signal lines to transmit a pair of balanced signals. Since the interference on the two signal lines is the same in magnitude and opposite in phase, the interference will be canceled in the end. Due to the low frequency range of audio, it is susceptible to interference in the case of long-distance transmission.

Therefore, as an anti-interference connection method, balanced connection is the most common in the audio connection of professional equipment. There are also two-core shielded cables used as audio cables in the connection lines of household appliances, but what it transmits is the left and right channels, which are two signals, which is not a balanced connection.

2. Unbalanced connection

Unbalanced connection is a connection method that uses only one signal line to transmit signals. Because this connection is susceptible to interference, it is only generally used in household appliances or in some cases with lower requirements

·

XLR Pro audio cable, XLR male right angle/XLR female

→ The specific connection method takes XLR connector as an example:

[Balanced connection] Pin 1 is connected to the shield, pin 2 is connected to the + end (also called the hot end), and pin 3 is connected to the-end (also called the cold end);

[Unbalanced connection] Pin 1 and pin 3 are connected to the shield, and pin 2 is connected to the + terminal (signal terminal). The choice of connection method generally depends on the specific requirements of the device for the interface. If you can use the balanced connection method, use the balanced connection method as much as possible. When making the connection, be sure to read the instructions on the panel first. It is best to read the relevant instructions and Require.

In some occasions, the device interface at one end may be a balanced interface, and the device at the other end may be an unbalanced interface. In the case where the requirements are not very strict.

Just use the balanced connection at the balanced end and the unbalanced connection at the unbalanced end. Pay attention to the corresponding pins. In the case of strict requirements, a conversion circuit must be used to convert balance to unbalance, or unbalance to balance.

195 series short lead, right-angle BNC male/straight-through BNC male

2. How to carry out quality inspection for BNC interface

The BNC interface is a very common video interface. As a coaxial cable connector, it is usually used for workstations and coaxial cable connection connectors, and standard professional video equipment input and output ports. The BNC cable has 5 connectors for receiving red, green, blue, horizontal sync and vertical sync signals. The BNC connector is different from the special display interface of the ordinary 15-pin D-SUB standard connector. It is composed of three primary color signals of R, G, and B, and five independent signal connectors for horizontal synchronization and vertical synchronization. Mainly used to connect workstations and other systems that require high scanning frequency. The BNC connector can isolate the video input signal, reduce the interference between the signals, and the signal bandwidth is larger than the ordinary D-SUB, which can achieve the best signal response effect.

So when using BNC interface, how to distinguish the quality of BNC connector?

First, the adsorption test can be carried out with iron absorption stones: in general, only the bayonet spring and the tail spring are made of iron material; the wire clamp and the pin are made of copper, and the other parts are made of zinc alloy.

Second, you can scrape the surface coating to see the material: use a metal sharp tool to scrape the surface coating to see the material intuitively, such as scraping the wire clip, pin, shielding sleeve coating to intuitively compare the product material.