Hello,
Today, I would like to share with you the DDF.
1- Introduction
Digital Distribution Frame DDF (Digital Distribution Frame)
Digital distribution frame, also known as high-frequency distribution frame, has more and more advantages in digital communication. It can make the connection of the digital code stream of digital communication equipment into a whole, from the rate of 2 Mb/s to 155 Mb/s signal The input and output of the DDF can be terminated on the DDF frame, which brings great flexibility and convenience to wiring, wire adjustment, switching, and capacity expansion.
Digital distribution frame is the wiring connection equipment between digital multiplexing equipment, digital multiplexing equipment and program-controlled switching equipment or data service equipment and other professional equipment. DDF is mainly used in: some optical network equipment, wireless base stations and office equipment, NGN, data communication equipment, etc.; DDF is also used in optoelectronic equipment. Optical network equipment has optical-to-digital conversion during networking, and DDF is generally required in digital signal transmission. At present, metropolitan area networks have the largest demand for DDF.
When wireless base stations, microwave base stations, and wireless office equipment are networked, signal transmission is also required in the site or in the computer room. This is also the need to use DDF. When we conduct wireless practices at various bases, this is the most common one.
Examples of common DDF are as follows:
Figure 1: 75 ohm BNC type connector DDF
Figure 2: 75 ohm L9 type connector DDF
Figure 3: 75 ohm SMB type connector wound type DDF
Figure 4: 120 ohm card-connected DDF
2- Function of DDF
DDF is a bridge that transmits signals between devices, and its basic functions are as follows:
1) Fixed wiring function: according to the circuit distribution requirements of the engineering design, the same speed, the same impedance, and the same direction, in the distribution.
The link mode of the communication link between the receiving and transmitting on the wire rack.
Figure 5: Wiring function
2) Line adjustment function: the same speed, the same impedance, and the same direction, the way of mutual connection between any receiving and any sending on the distribution frame.
Figure 6: Line adjustment function
3) Transfer function: the same speed, the same impedance, and different directions, the way to connect between any receiving and any sending on the distribution frame.
Figure 7: Transfer function
4) Self-loop test and online test function: same speed, same impedance, different directions, loopback test in the distribution frame to locate link and port faults.
Figure 8: Self-loop test and online test function
3- DDF common connectors
Figure 9 L9 type connector
Figure 10 BNC connector
Figure 11 C5 type connector
Figure 12 SMA/SMB/SMC connector
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