Micro Linear Corp. announced the ML6431, the newest member of their Genlock product family. The ML6431 and it's counterpart, the ML6430, play an important role in the thousands of products that use digital video such as multimedia PCs, video capture, MPEG (encoding and decoding), large-screen TVs, LCD projectors, video editing systems, etc. The ML6431 is especially effective in VGA applications, as it is designed to work with up to a 70MHz clock.

In digitizing applications, the Genlock chips extract the crucial timing signals from an analog video input (NTSC, PAL or VGA) and uses them to generate the waveforms needed for the digitizing process. Both products are designed to provide a stable clock from an analog video signal, and to provide low jitter timing pulses for clamping, decoding, blanking and processing video signals. Advanced analog techniques provide multi-standard and non-standard operation from a single crystal or external asynchronous clock source.

The ML6430 and ML6431 handle VCR timing glitches and variations created by head switching, tape dropouts, missing sync pulses, freeze frames, high speed playback and camcorder gyro errors. They are designed for high noise immunity, insensitivity to varying signal amplitudes, overmodulated color carriers, and sync glitches.

Pin selectable preset modes allow operation for most video standards (PAL, NTSC, and VGA) in simple stand-alone mode without having to use the serial bus. For more demanding high-end applications, a two-wire serial control bus is available for full control of all of the ML6430 and ML6431's features.

Additionally, The ML6430 and ML6431 are ideal for clock generation in MPEG encoders, high performance display timing, and video editing.

As a former user of Micro Linear parts I can be one of their worst critics about some of the things the company does in its designs. But these parts, evolving over the last couple of years, are winners and the only real criticism I have is the name! And I'm not getting used to it. Genlock is a function in broadcasting when a device is locked to another (normally remote) device. There is nothing in genlock that says things are stable, though you hope they are; I could tell you stories about engineering the most remote camera at a broadcast of a horse race with the whole of a country's network genlocked to a camera that was in an incredibly unstable mood, but was miraculously working the score or so times that it went on air as the genlock source in one afternoon. (The term Genlocker, incidentally, is a registered trademark of Sony.) So, Video Genlock is a catchy marketing name but it doesn't describe what the product does.

The ML6431 is really a high-frequency timebase corrector (TBC) without the video path complications. Distortions can be caused by repeated timing jumps and jitter, transient jumps and jitter, sync pulse amplitude and risetime errors, color burst risetimes, amplitude and jitter. Just about whatever ugly analog signal you throw at the product you will still get a stable clock suitable for re-generating -- clean -- all the analog pulses in the video signal as well as the sampling signals for the ADC(s). If I was still in the business I would certainly be thinking about the consumer TBC market that might be out there for the remaining years of analog video recorders, cameras and PC outputs. A quick sketch says that one of these chips plus video processing, high-frequency ADCs and output filters and buffers could be built for about $25. There could be an interesting size market. Micro Linear are after bigger fish, however, and I would expect to see them getting large design wins for displays and MPEG encoders. This particular part is ideal for VGA to DV conversion circuits.

The ML6431 is sampling now with production next month in a 32-pin TQFP and is priced at $10.50 in 1000-piece lots.