Differential Signals In Coaxial Cables

Coaxial cables are the mainstay for long-distance signal transmission at radio frequencies. They are not generally used for digital data or pulse transmission due to their bandlimited nature. However, they can be used to transmit signals in specialty analog applications, including modulated signals that will provide data to a receiver. The use of coaxial cables can also be extended to another case: differential analog signals.

The use of differential signals in analog applications is uncommon; this type of signaling may be used in specialty measurement applications with a custom-built differential driver, or a differential op-amp. That being said, it is still something supported by common component sets, and so it is possible to route differential analog signals into a connector, including an SMA connected to a coaxial cable. One instance where this might be used is in a noisy environment, where the goal is to take advantage of the cable shielding to prevent noise pickup.

If you are planning to transmit a coaxial differential signal over coaxial cables, pay attention to some of these design points. Eventually, you may find that the frequency or power handling becomes problematic in your system and you will require a different approach.