The spaceship among converters TU Braunschweig research project on digital-to-analogue converters enables boundary-shifting
For an audio file to be a pleasure to listen to, a digital-to-analogue converter (DAC) must convert the digital MP3 information into an analogue audio track. A high-performance DAC doesn’t even break a sweat at the 44,100 sampling operations per second required. But as soon as something like the future 6G mobile network is involved, even the best DACs reach their limit of a few billion sampling operations (gigasamples/second). Professors Vadim Issakov and Thomas Schneider from Technische Universität Braunschweig want to turn the existing rules for digital-to-analogue converters upside down by 2028. Supported by the German Research Foundation (DFG), they are pursuing an idea that could turn mediocre DACs into true all-rounders.
For the new converters, the research team combines expertise in high-frequency technology and chip design. Photo credits: Kristina Rottig/TU Braunschweig
‘Orthogonal sampling’ is at the heart of the DFG’s ‘HighDAC’ project. Researchers from the Thz-Photonics Group and the Institute for CMOS Design want to place a whole series of digital-to-analogue converters orthogonally next to each other, like Lego bricks, and add their capabilities. “With this approach, we have the potential to simply ignore the classical physical limit of DACs and even break through the 100 gigahertz barrier. To do this, we build the wide spectrum like a jigsaw puzzle made up of many small bandwidths. To put it simply, we are turning three Fiats into a Ferrari and 300 Fiats into an interstellar spaceship,” says Professor Thomas Schneider.
The feasibility of the approach has been published by Professor Thomas Schneider’s research group in the ‘IEEE Open Journal of the Communications Society‘. Together with the chip design expertise of Vadim Issakov’s team, the successfully simulated approach will be put into practice in the ‘HighDAC’ project. “Together, we will test the possibilities and limits of orthogonal sampling over the three years of the project. We now need a suitable chip design to bring the building blocks together in the smallest possible space,” says Professor Vadim Issakov.
Shifting the boundaries of radar, sensors and communications
By the end of the project, not only could the world’s fastest DAC be in place, but the concept could be scaled to even higher bandwidths. The project has already had significant synergy effects with other research projects at TU Braunschweig. For example, the super DACs could drastically increase the speed of mobile data transmission for the upcoming new mobile communications standard, which is being investigated in the ‘6G-RIC‘ project. Radar systems, such as those being developed by Vadim Issakov and his team in the ‘Tiempo‘ project, will also benefit. The high-bandwidth DAC will enable radar sensors with unprecedented resolution, such as a high-resolution three-dimensional radar image in real time.
A strong research team is needed for the new converters: (from left to right) Dr Janosch Meier, Prof. Thomas Schneider, Melikhan Bekir, Deepanshu Yadav, Prof. Vadim Issakov and Younus Mandalawi. Photo credits: Kristina Rottig/TU Braunschweig
About the project
The German Research Foundation (DFG) is funding ‘HighDAC’ (High-Bandwidth and High-Sampling Rate Orthogonal Sampling-Based DAC using Low-Bandwidth Electronics) with around 740,000 euros. The joint project by Professor Thomas Schneider and Professor Vadim Issakov will run for three years, from January 2025 to December 2027.