The Digital Lag

I discussed the issue of latency many times here on this blog. Typically understood as the delay of a reaction on human input. This has been the issue (and one of the key performance metrics) in computer gaming. There is a human interface device (HID) controller such as a joystick, it processes the physical inputs, transmits them to the computer or a gaming console that does it's own processing and renders the output scene which is then pushed as a stream of digital signals to a display. The display (monitor) also has its own lag - a parameter that differentiates gaming displays from (cheaper) office displays.

(The reduction of) the lag is also what is driving mobile devices such as phones and tablets to support higher screen refresh rates. Also what from the very beginning was the iPhone differentiator was the smoothness of the reaction, something that Android was struggling with for several years. Google even had its special focus "Project Butter" - the effort in Android 4.1 Jelly Bean to significantly improve the OS's responsiveness and speed, making the user experience feel "buttery smooth".

The lag is inherent to all digital systems. And is also responsible for the still relatively high markets' reservation to digital lighting control systems. In the "analog days" there was no lag - no processing. A wall switch was closing the electrical circuit and the current was instantly flowing through the light bulb, lighting it up.

With LEDs and digital, we now have drivers, that have lag (although not that really high), control systems (the older generations all have the lag, often very significant) and even sensors introduce lag, often by design.

Users hate the lag. Although they have learned to live in laggy environments. The lighting system we have inherited in our own new office in a class-A modern office building has very bad lag. Enter the restroom, stand in the dark for 2 seconds, and the lights will come up. Very bad. If there was a switch with a 2-second lag, most people would be quick enough to press it more than once, as if it did not work for the first time. If it was a toggle switch, you would often turn the light off (on a 2nd press) and on again (on the 3rd press).

The (lack of) lag is one of the very rarely discussed feature of properly implemented Bluetooth NLC control systems. If you want to dive deeper into why it is so much better, this post and the follow up discussion is a good starting point. I do believe the lack of the lag is one aspect of Bluetooth NLC that contributes highly to the popularity of this technology. It all is instant and feels "analog". We have put a lot of attention to reducing the lag at all layers - both from the architectural standpoint and the software implementation too. Customers say the Silvair system is "buttery smooth". This is this touch of luxury and confidence, that is really hard to express in datasheets, but contributes a lot to the overall impression and the accelerated rate of adoption.