2020
Autores
Ramires, A; Bernardes, G; Davies, MEP; Serra, X;
Publicação
CoRR
Abstract
In this paper, we present TIV.lib, an open-source library for the content-based tonal description of musical audio signals. Its main novelty relies on the perceptually-inspired Tonal Interval Vector space based on the Discrete Fourier transform, from which multiple instantaneous and global representations, descriptors and metrics are computed-e.g., harmonic change, dissonance, diatonicity, and musical key. The library is cross-platform, implemented in Python and the graphical programming language Pure Data, and can be used in both online and offline scenarios. Of note is its potential for enhanced Music Information Retrieval, where tonal descriptors sit at the core of numerous methods and applications.
2020
Autores
Bernardes, G;
Publicação
Proceedings of the International Conference on New Interfaces for Musical Expression
Abstract
Audio content-based processing has become a pervasive methodology for techno-fluent musicians. System architectures typically create thumbnail audio descriptions, based on signal processing methods, to visualize, retrieve and transform musical audio efficiently. Towards enhanced usability of these descriptor-based frameworks for the music community, the paper advances a minimal content-based audio description scheme, rooted on primary musical notation attributes at the threefold sound object, meso and macro hierarchies. Multiple perceptually-guided viewpoints from rhythmic, harmonic, timbral and dynamic attributes define a discrete and finite alphabet with minimal formal and subjective assumptions using unsupervised and user-guided methods. The Factor Oracle automaton is then adopted to model and visualize temporal morphology. The generative musical applications enabled by the descriptor-based framework at multiple structural hierarchies are discussed. © 2020, Steering Committee of the International Conference on New Interfaces for Musical Expression. All rights reserved.
2020
Autores
Margarida Pessoa; Cláudio Parauta; Pedro Luís; Isabela Almeida; Gilberto Bernardes;
Publicação
Abstract
This paper presents an overview of the design principles behind Digital Music Instruments (DMIs) for education across
all editions of the International Conference on New Interfaces for Music Expression (NIME). We compiled a comprehensive catalogue of over hundred DMIs with varying
degrees of applicability in the educational practice. Each
catalogue entry is annotated according to a proposed taxonomy for DMIs for education, rooted in the mechanics of
control, mapping and feedback of an interactive music system, along with the required expertise of target user groups
and the instrument learning curve. Global statistics unpack
underlying trends and design goals across the chronological
period of the NIME conference. In recent years, we note
a growing number of DMIs targeting non-experts and with
reduced requirements in terms of expertise. Stemming from
the identified trends, we discuss future challenges in the design of DMIs for education towards enhanced degrees of
variation and unpredictability.
2020
Autores
Gomes, R; Duarte, C; Pedro, JC;
Publicação
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
Abstract
Typical polar digital power amplifiers (DPAs) employ unit-cells operated in class-E or D-1, denoting a switched-resistance operation which degrades linearity. Besides introducing higher demand on digital predistortion (DPD), it also requires extra quantization bits, impacting the overall efficiency and system complexity. To address this, the present work makes use of an optimized constant-current cascode unit-cell which is combined with reduced conduction angle to achieve linear and efficient operation, while minimizing the effort on DPD and/or calibration. A design strategy is developed which focuses on the cascode bias voltage and transistor relative dimensions as design parameters, allowing cascode efficiency optimization without compromising linearity or reliability. A single-ended polar switched constant-current DPA is implemented in 180-nm standard CMOS. Continuous-wave measurements performed at 800 MHz demonstrate an output power of 24 dBm with a PAE of 47%. The DPA dynamic behavior was tested with a 64-QAM signal with 10 MS/s, achieving an average PAE of 20.9% with a peak-to-average power ratio (PAPR) of 8.7 dB and adjacent-channel leakage ratio (ACLR) = 40.34 dB. These results demonstrate comparable performance with the prior art while using only 6-bits clocked at 100 MHz baseband sampling frequency.
2020
Autores
Weber, S; Duarte, C;
Publicação
IEEE Solid-State Circuits Magazine
Abstract
A high production yield,
2020
Autores
Sulun, S; Tekalp, AM;
Publicação
Signal, Image and Video Processing
Abstract
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