I can't tell you the ruckus my last column has raised. Readers were thrown by my reference to our upcoming "special seminar series" and by my willingness to include digital signal processing in the "call for experts." The new seminar series-successor to the conference on analog and mixed-signal applications that I have been chairing for many years-is set for Oct. 5 to 7 at the Westin hotel in Santa Clara, Calif.
There are some engineers, in fact, who wonder if I am a turncoat, a traitor to the analog cause. Analog and digital design realms are not exactly armed camps, trying to undermine each other. But there is a difference between analog and digital thought processes.
As much as I'd like someone to review data network, digital TV and multimedia standards at the conference, I'd also like to know what kind of work-specific voltages, currents, frequency responses and impedances-goes into driving those displays and cables. What I'm building is the latest and greatest incarnation of the annual analog/mixed-signal confab. But this year will see more attention to engineering detail.
Whether an engineer should use standard analog building blocks in a design or market-focused parts like ADSL line drivers, sigma-delta audio converters or NTSC-video format converters can only be understood in an applications context. This conference will be rich on engineering insights: If I have my druthers, engineers will come away with a deep understanding of how these up-tempo applications of analog and mixed analog-digital technology work, where the boundaries of analog and digital realms are placed, and where building blocks or ASSPs will get the job done. And where there is an analog thought process at work, that will be evident.
At the recent International Microwave Symposium, Motorola touted its achievements in getting LDMOS power transistors to be linear all the way up to 2.4 GHz. Transistors, remember, are inherently closer to switching devices than to amplifiers. But Moto's wireless applications manager, Mark Williams, came as close as anyone to underlining an analog mind-set in his comparisons with the vacuum-tube amplifiers once used for high-power RF.
"FETs are more like triodes in their transfer characteristics," Williams said. "Bipolar devices are more like pentodes: There's only a half dB between the linear region and hard saturation."