Why Keyssa Built a Better Connector: Part 1 – Signal Integrity

By Steve Venuti
VP Marketing, Keyssa

We have all experienced the frustrations of mechanical connectors – they break, they leak, they lose connection….it shouldn’t be surprising; data connectors have been around for more than 100 years. Keyssa has changed all that by creating its wireless connector, eliminating the mechanical portion of the connector and replacing it with solid-state technology. We designed this to behave just like a connector – bring two devices together and they connect; pull them apart and they disconnect.

 

 

In a series of blogs that focuses on why Keyssa’s connector provides benefits that mechanical connectors do not provide, we start with a fundamental issue with mechanical connectors, signal integrity.

Signal Integrity: Issues with Mechanical Connectors

Metal is such a wonderful conductor of signals – cheap and fast…no wonder it is the “go to” choice for connector design. But as speeds increase, so do the challenges of managing signal integrity over metal connectors and cables. Minimizing crosstalk, bandwidth degradation, signal loss, distortion, and reflections due to impedance mismatches – it’s not about losing a little signal strength…it’s about how much signal will be left given you much you will lose with every interconnect.

Keyssa’s solid-state wireless connector transmits its signal a very short distance over air or through the shell of one device to another…no metal between transmitter and receiver, so traditional concerns like distortions and impedance mismatch due to connectors don’t apply. But more than that, Keyssa’s connector has built-in signal processing, equalization, and de-emphasis.

With Keyssa’s solution, the signal on the receiving side will have the same properties as the signal on the transmit side, with no degradation or loss of signal integrity. In essence, Keyssa’s RF link not only provides the connection itself, but also has the function of a re-driver or retimer that would correct for poor signal integrity in a system that needs this kind of correction.

To illustrate this, we measured signal strength in a typical application with a copper cable and a mechanical connector and compared that to the same signal with a Keyssa link replacing the connector. The results are shown below.

Identical set-up running at 3 Gbps running over a 6-meter copper cable and Keyssa KSS104M

 

The Proof is in the Bit Error Rate (BER)

Bit error rate (BER) is defined as the percentage of bits that have errors relative to the total number of bits received in a transmission. BER is usually expressed as 10 to a negative power. For example, if a transmission has a BER of 10 to the minus 4, this means that of 10,000 bits transmitted, 1 had an error.

Traditional 802.11 (Wi-Fi) technology has a BER of between 10-3 – 10-7. Although both are wireless, it would be unfair to compare Keyssa’s BER to that of Wi-Fi. Keyssa’s technology is near-field and a point-to-point connection –  the RF antenna is highly directional. Besides, Keyssa is not solving problems addressed by other wireless technologies; Keyssa is using wireless to solve problems facing metal. Connectors.

Let’s look at the BER requirements for some common high-speed protocols – all traveling over wire and connected with mechanical connectors.

Because of its signal processing, equalization and pre-emphasis, a Keyssa link is specified at a BER equal to or better than a wire: Minimum of 10-12 and in many cases 10-15

There are billions of connectors in the world that perform quite well. Not every application requires Keyssa’s solid-state connector. But industry trends point to increasing challenges for traditional metal connectors. Faster data rates lead to more challenging signal integrity issues and more EMI/RFI – all of which has to be dealt with in the design of a product. The mechanical connector has not materially changed in over 100 years; at its core, it’s simply metal touching metal. For many connector applications, this model has reached its end of life.

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