What is in this article?:
- The evolution of production switchers
- Today’s capabilities
- The next step
It’s funny how our business reinvents itself on a regular basis. Even funnier still is how commodity IT technology has been in the forefront of switcher developments of late.
For decades, production switchers were rigid in their architecture. Each M/E bank fed into an internal router but cascaded together in a fixed structure. M/E 1 could not have M/E 3 as a source, though the reverse was possible. There is a simple reason for this: Analog switchers could accommodate only a fixed amount of delay, and cascading effects busses together lengthened the latency of the signal.
To accommodate this, fixed delays were inserted where appropriate in a switcher so that when cascaded, things still would work. In analog color composite systems, this was necessary to keep the color subcarrier in phase.
A game changer
In the late 1970s, Grass Valley introduced a switcher (Model 300) that, although still analog, broke that paradigm by using delay lines of various lengths to allow “infinite re-entry.” This was a game-changing innovation. It was complex and expensive, but it sustained the 300 as the premier switcher for many years. For years, there were “300 emulation modes” in some switchers to allow TDs who are reticent to change to do things in familiar ways, long after digital switchers killed the market for analog production switchers altogether.
Analog switchers were expensive for many reasons, but it is important to remember that they were truly a system. Replacing a single module might require extensive setup of the entire switcher for (especially) levels and phase. This meant that initial checkout and fine tuning in the factory was labor-intensive and required considerable time while electronics “cooked” together. Digital switchers can be produced one board at a time and don’t need to be checked and tuned as a system to anything like the precision necessary in the analog world.
Feature creep in digital switchers is often a matter of writing new code, though in some instances that code must be run in FPGA chips, which have extraordinary capabilities. Enabling features not purchased initially can be as simple as inserting a code to authorize your use, since it is not practical to deliver many versions of software with many combinations of features to users all over the world.
