Jonas Roth


Last Name

Roth

First Name

Jonas

ORCID

0009-0004-0419-5041

Organisational unit

09695 - Studer, Christoph / Studer, Christoph

Filters

2023 - 20253
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Publications 1 - 3 of 3
  • Graetli: A Microcontroller-Based DSP Platform for Real-Time Audio Signal Processing
    Item type: Conference Paper
    Roth, Jonas; Krebs, Silvan; Studer, Christoph (2025)
    This demonstration presents graetli, a standalone digital signal processing (DSP) platform for real-time audio applications, built around the Electrosmith Daisy Seed microcontroller platform. graetli features high-quality analog audio I/O, a zero-latency analog dry signal path, a user interface with programmable potentiometers, and a rugged enclosure. graetli is suitable for both performance interaction and algorithm prototyping. To showcase its capabilities, we implement a frequency domain artificial reverberation algorithm. Conference visitors are invited to interact with the platform and experience the real-time DSP reverb algorithm.
  • An Aliasing-Free Hybrid Digital-Analog Polyphonic Synthesizer
    Item type: Conference Paper
    Roth, Jonas; Keller, Domenic; Castañeda Fernández, Oscar; et al. (2023)
    Proceedings of the International Conference on Digital Audio Effects ~ Proceedings of the 26th International Conference on Digital Audio Effects
    Analog subtractive synthesizers are generally considered to provide superior sound quality compared to digital emulations. However, analog circuitry requires calibration and suffers from aging, tem perature instability, and limited flexibility in generating a wide variety of waveforms. Digital synthesis can mitigate many of these drawbacks, but generating arbitrary aliasing-free waveforms re mains challenging. In this paper, we present the +−synth, a hybrid digital-analog eight-voice polyphonic synthesizer prototype that combines the best of both worlds. At the heart of the synthesizer is the big Fourier oscillator (BFO), a novel digital very-large scale integration (VLSI) design that utilizes additive synthesis to generate a wide variety of aliasing-free waveforms. Each BFO produces two voices, using four oscillators per voice. A single oscillator can generate up to 1024 freely configurable partials (harmonic or inharmonic), which are calculated using coordinate rotation digital computers (CORDICs). The BFOs were fabricated as 65 nm CMOS custom application-specific integrated circuits (ASICs), which are integrated in the +−synth to simultaneously generate up to 32 768 partials. Four 24-bit 96 kHz stereo DACs then convert the eight voices into the analog domain, followed by digitally controlled analog low-pass filtering and amplification. Measurement results of the +−synth prototype demonstrate high fidelity and low latency.
  • Live Demonstration: An Aliasing-Free Hybrid Digital-Analog Music Synthesizer Prototype
    Item type: Other Conference Item
    Roth, Jonas; Keller, Domenic; Castañeda Fernández, Oscar; et al. (2023)
    2023 IEEE International Symposium on Circuits and Systems (ISCAS)
    Analog subtractive sound synthesis is widely used in music production since the 1960s, with popular synthesizers from Moog Music, Sequential, and ARP Instruments. While analog synthesizers are considered superior in terms of sound quality compared to their digital counterparts, analog circuitry typically suffers from temperature instabilities, component variations, and lack of flexibility. Digital music synthesizers can avoid all of these drawbacks, but it is challenging to design digital oscillators and filters that do not cause aliasing artifacts and sound as impressive as their analog counterparts. In this live demonstration, we show a polyphonic hybrid digital-analog music synthesizer prototype in which the oscillator signals are aliasing-free and generated by an FPGA, whereas the filters and amplifiers are implemented with analog circuits, thus combining the best of both worlds.
Publications 1 - 3 of 3