“It’s a digital world, but we always need an analogue bridge to it”

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Analog Devices (ADI) offers signal processing and conditioning products. It caters to several markets including communication infrastructure, industrial, healthcare, automotive and consumer. ADI has close to $3-billion turnover and 60,000 customers worldwide.

Somshubhro Pal Choudhury (Som), managing director-India, Analog Devices, spoke to Abhishek Mutha of EFY about the incremental versus fundamental change in research, the challenge faced while coming up with an advanced driver-assistance system, and why it is still an analogue world even though everything around us is digitised


Q. In an almost wholly digital world, where do analogue components stand?
A. We live in a digital world but all of us interface to the physical world, which is analogue. Be it speech, image, temperature or radio signals, these are all inherently analogue. These analogue signals need to be captured, filtered or conditioned, amplified, and fed into the digital world using an analogue-to-digital converter, and finally processed digitally. Then the information goes back from this digital world to the analogue world. This is called the analogue signal chain. It would probably be apt to say it is a digital world but there is always an analogue bridge to the digital world.

Q. Usually, while converting data from analogue to digital, we lose some information. Then why is conversion given so much importance?
A. Today, we have to capture all the physical world information, convert it, process it, store it, and finally interact back to the physical world by sending some control signals. The most essential and important thing in this process is conversion from analogue to digital signals to process them.

You are absolutely right that we lose some information, but in the end it is all about precision. For example, while measuring temperature using a digital thermometer, the first question that arises is the precision required of the measurement—whether it is 98.4 or 98.45. An extra decimal point signifies more accuracy and precision of the converters. Depending on the precision requirement, the right converter should be picked.

Q. From a conversion standpoint, precision must be a big challenge. Are there any other challenges you would like to talk about?
A. Yes, there are several challenges while converting data from analogue to digital. Analogue signals are continuous signals, not discrete with respect to time, whereas digital signals are a distinct ‘0’ or ‘1.’ An analogue signal, being a continuous signal, gets highly impacted by the noise. The noise is contributed by the electronic circuitry where the analogue portion resides, thermal environment, interference and cross-talk even from other associated devices. The challenge is the conditioning of the incoming signal, i.e., eliminating or reducing the noise. In other words, it is signal filtering to minimise noise.

Low power is another challenge gaining importance from a system’s perspective. Here power refers to the amount of energy required by the converter to convert each bit of information.

Also, in the digital world there is far better correlation between simulation (using CAD tools, for example) and the actual silicon out of the fabrication unit, whereas in the case of analogue there is still a considerable difference between the two. As it is not possible to fabricate multiple times and correlate with the simulation, this is a critical challenge.

At last, in the conversion process, it is necessary to hold a signal for a certain time before processing and converting it into digital. The more the electronics is involved, the higher the precision needed and hence the larger the delay. Talking about high-performance converters and precision converters, these are orthogonal (independent) in terms of requirement and design challenges. But the market is demanding both higher precision and higher performance together. These are some of the challenges from a conversion standpoint.

Q. We are seeing fewer revolutionary changes in the current hi-tech industry. Have research priorities changed due to a mature market?
A. Research is fundamental to innovation, but as the hi-tech industry has matured the innovations from research are more of an incremental rather than a fundamental change. Let’s take the case of semiconductors. Silicon has been used for long now but there is no transition to a fundamentally different material. Moore’s law has been followed by packing more transistors, higher performance and lower power on silicon but again that is an incremental change. As the industry matures and goes mass market, that typically will be the nature of the innovations.

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