Why do we use 50 ohms

It really is as simple as that. So in the field of RF and Microwave where there is a trade-off between the losses and power, transmission line is choosen at 50 Ohm impedance value. The attenuation of coaxial cable is addressed in Section 7. Coaxial cables are often required to carry high power signals.

This is useful for understanding how your S-parameters might change when you switch your reference media e. We have only scratched the surface of what is possible to do with Altium Designer on Altium You can check the product page for a more in-depth feature description or one of the On-Demand Webinars. Zachariah Peterson has an extensive technical background in academia and industry.

He currently provides research, design, and marketing services to companies in the electronics industry. Prior to working in the PCB industry, he taught at Portland State University and conducted research on random laser theory, materials, and stability. His background in scientific research spans topics in nanoparticle lasers, electronic and optoelectronic semiconductor devices, environmental sensors, and stochastics. Mobile menu. Explore Products.

Altium Community. About Author Zachariah Peterson has an extensive technical background in academia and industry. More content by Zachariah Peterson. Thus, 75 Ohm Coax is the closest fit, offering not only low signal attenuation loss , but also relatively low capacitance.

This combination of low attenuation and capacitance effectively make 75 Ohm Coaxial Cable the cable of choice for practically all types of digital audio, digital video and data signals. This is why every cable TV company uses 75 Ohm coax for distributing its digital video channels as well as its broadband internet data signals. Direct broadcast satellite dishes and over-the-air HDTV antennas also require 75 Ohm Coaxial Cable to ensure that all of the digital channels transfer down the cable with the lowest loss and distortion possible.

We sell a lot of these cables to radio and television broadcasters and production companies to interlink their equipment. Finally, one last crucial point in regards to coaxial cables.

The Impedance of the various devices being connected as well as the Coaxial Cable itself must match. So if you are, for instance, connecting a 75 Ohm video camera connection to a studio monitor, the coaxial cable must also be 75 Ohm AND the connectors on the coaxial cable i. BNC connectors must be 75 Ohm in Impedance. Every single time you have a mismatch in impedance, say between a 50 Ohm Coaxial Cable and a 75 Ohm Coaxial Connector i.

BNC , a standing wave develops. A standing wave is a signal reflection that is essentially wasted. These losses add up and can eventually degrade the signal to the point that it is unrecoverable or distorted. Some coaxial cable manufacturers will cut corners in this regard.