Acoplamiento de impedancia Balum

Impedance Transfer Boxes
There are two types of impedance transfer boxes, namely, 120 ohm-75 ohm transfer box with the BNC socket and 120 ohm-75 ohm transfer box with the SMB socket. The dimensions(L x W x H) are 488 mm x 40 mm x 28 mm, that is 19.2 in. x 1.6 in. x 1.1 in. The two transfer boxes differ only in the 75-ohm coaxial connector. One is the SMB and the other is BNC, which can beadopted based on actual conditions.
Figure A-1 shows the method for using the impedance transfer box.
Figure A-1  Method for using the impedance transfer box
[pic]
|1. 75-ohm coaxial cable|2. Coaxial cable connector |
|3. RJ45 connector |4. 120-ohm twisted pair |


The impedancetransfer box connects with the 75-ohm cable through the SMB or BNC coaxial connector at one end, and connects with the 120-ohm cable through the connector at the other end.
The 75-ohm cable connects withthe SMB female connector or the BNC male connector at one end, and connects with the cabling rack or directly with the equipment at the other end. The 120-ohm cable connects with the 8-pin connectorat one end, and connects with the cabling rack or directly with the equipment at the other end.
The method for crimping the 75-ohm cable into the coaxial connector is not described here. The specialcrimping pliers are needed to crimp the 120-ohm cable into the RJ45 connector.
Figure A-2 shows the appearance of the RJ45 connector.
Figure A-2  Appearance of the RJ45 connector
[pic]
Table A-1lists the pin assignment of the RJ45 connector connecting with the 120-ohm twisted pair.
Table A-1  Pin assignment of the RJ45 connector of the 120-ohm twisted pair
|Pin No. |Definition ||1 |RX- |
|2 |RX+ |
|3 |PGND |
|4 |TX- |
|5 |TX+ |
|6...