Signalling the Future for DSP

Author : Aneet Chopra - EVP Marketing & Product Management, XMOS

18 June 2024

We’re so used to the devices that we tend to utilise every day, and often they seem fairly unremarkable to us - just a basic expectation of modern life. But the path to their existence has been anything but mundane. Any technology is, more often than not, part of a constantly changing market in which designers are always reimagining, refining and reinventing their ideas. This may be to gain a competitive edge, improve the user experience (UX), or simply to correct wrinkles in performance.

Such perpetual change is partly driven by the need to communicate in a more sophisticated manner. As items of electronics become better able to interact, both with us as users and with one another too, we need them to recognise and interpret a wider range of inputs and signals. This is especially relevant in the Internet of Things (IoT) era. As products being developed need to process increasing quantities of data and act autonomously, they must be able to recognise stimulus and know how to respond to it.

With this requirement comes a need to have a common frame of reference by which we can measure and understand these signals, then build a baseline for optimum communication. This is where digital signal processing (DSP) comes in.

Enter DSP

DSP silicon has long played a crucial role in many of the devices we use on a daily basis. Just as it sounds, this works by digitising the functions of analogue signal filters. DSP takes real-world inputs and manipulates the maths behind it in specific ways to achieve the desired output. In many areas, DSP has taken over from analogue filters - which, while well-established, also come with well-established limitations. A physical filter is final once it has been fixed - meaning that as components gradually deteriorate, their values will drift over time. The longer they are used, the more likely that results are going to slowly degrade.

Perhaps unintuitively, DSP can offer a far more rugged alternative than a physical filter. Because filters are coded digitally, designers are able to build in a robustness that can’t always be matched by their physical counterparts. Additionally, DSP allows the introduction of very specific effects that are more difficult to achieve with analogue filtering. And that’s not just in terms of ‘cleaning’ the audio to better isolate and understand the signal within, but also augmenting it - by applying specific levels and types of compression, modulation, equalisation, etc. Once this refinement is complete, the modified signal can be broadcast elsewhere as the user requires. This all underlines the key qualities of DSP - consistency and efficiency. It can be trusted to receive and process vital information quickly and effectively.

What it means

So, why is DSP so important to the future of the industry? And what specific role can it play in increasing the efficiency of how devices communicate? These days, as various creative innovations emerge and entirely new markets spring up, we’ve seen a diverse market of small niches appear, each with unique requirements. In an ideal world, every company designing a product has the money, time and supply to cater to their chosen niche with the perfect hardware. However, with the sheer number of use cases and applications, that’s not realistic. Manufacturers have to work within their limits, finding the most bang for their buck on a set budget.

In that context, the ubiquity and utility of DSP is incredibly valuable. Engineers might not know exactly what component or budget is available to them at the start of a project - but they do know that DSP is a reliable, established means of building important functionality into their designs. That’s especially true in industries that experience a rapid rate of alteration or technological development - such as consumer electronics, manufacturing, automotive, etc. In fast-moving fields, technologies like DSP represent something of an open standard or a known quantity - providing a point of reference for performance, plus a versatile tool that professionals can rely on in a design process full of change. Given the breadth of technologies that need to be able to take advantage of DSP, however, it’s also important to consider exactly what sort of DSP solution should be sought.

Purpose-built vs general purpose

Simply put, there are 2 potential approaches for integrating DSP into a device. These are either choosing a dedicated DSP solution, designed with the sole intention of delivering the highest quality DSP possible; or alternatively integrating a more general solution that delivers DSP along with other capabilities/functions.

It’s obvious that a system designed with only DSP in mind is likely to offer a higher level of operational performance, whether that’s a question of efficiency or precision. Such a component is going to have been designed and constructed specifically to deliver that service. However, opting for such an approach makes it likely that the component will have a higher cost, require greater space and power, plus prove more difficult to integrate into the design than an all-purpose solution. Furthermore, the resulting system is going to be horrendously inefficient at anything that isn’t DSP related - so if extra functionality is needed, it will have to be found elsewhere. All of that means a higher bill-of-materials (BoM), longer time-to-market, plus trickier technical processes to bring everything together. That’s not a compromise that most designers or manufacturers are willing to make.

This brings us to the more versatile alternative. An arrangement that allows for DSP amongst other functions - or even, ideally, one that allows manual configuration of the level of DSP required - will strike at the heart of these challenges. For one, it’s easier to integrate the component, as engineers don’t have to compensate for the lack of connectivity and functionality in a pure DSP solution, or deal with the peripherals and control elements that come with such a part. Costs are saved not only on the individual component itself, but also on not using multiple components to deliver the same set of functions that a general solution can. Furthermore, with the device taking on multiple roles within the final design implementation, the design process - and thus the time-to-market - will be markedly quicker.

It's also true that, as components are made obsolete, more versatile alternatives have adapted to the point that they can deliver the levels of DSP that previously required a specialist part. Here at XMOS, one example is asynchronous sample rate conversion. The company’s xcore.ai solution has found a niche in converting signals from 44.1kHz (CD quality sound) to 48kHz (.mp3 output), as the multi-core architecture employed makes it very effective at synchronising different clock rates.

In years gone by, this would have demanded an expensive, distinct system. General DSP is now, however, of a high enough quality to do so itself - thus allowing replacement of obsolete predecessors at a reasonable cost. So where else is that true? Where will we see DSP rise to the fore in the coming years?

DSP predictions

The most visible home of DSP for many will be in consumer electronics. While AI will inevitably elevate the functions of DSP to a new level, the standards of audio processing in products like smart speakers, soundbars, TVs and headphones will all rise - in part thanks to DSP’s growing ability to detect, clean and process input data. We’ll be able to deliver commands from further away, with more complexity leading to better results.

Distance and clarity are also major considerations on the factory floor. DSP’s ability to suppress or remove noise can have a real-world impact on industrial systems, enabling voice-controlled safety measures to protect employees around heavy machinery. It can also detect specific noises or patterns within machines that can help manufacturers to pre-empt maintenance requirements before a human would.

That sort of refinement is also present within the automotive market, where we’re seeing an explosion of new electronics and consistent interest in voice control. DSP is going to underpin cockpit systems, whether that’s something as conventional as changing the radio station, or as trailblazing as instructing an autonomous vehicle to take you to your destination.

All of these examples show us just how DSP can start to elevate the myriad of devices we interact with each day. What appears on the surface as a string of algorithms can transform our ability to control our immediate environment - and will continue to do so.