An electronically tuneable inductance with extended frequency range
The extension of the usable frequency range of an electronically tuneable inductance circuit is investigated. By means of numerical and analytical studies, the transistor-internal reverse transfer capacitance can be identified as a frequency-limiting element, which must be minimised. This is achieved by circuitry-wise compensation of the capacitive effect by introducing an additional inductance. The concept is verified through measurements of the practical implementation and shows an extension of the frequency range by two octaves throughout the VHF range, which proves beneficial for applications such as broadband matched and tuneable transmission lines, amplifier circuits, oscillators, or filters.
Experimental proof-of-principle of a passive, nearly reciprocal, transistor-based tuneable RF inductance
An innovative approach for tuneable reactances using the example of electronic inductances is introduced and the operation principle affirmed by measurement. Hitherto solutions for variable inductances often lack applicability in serial paths or do not exhibit passive behaviour. The presented circuit shows, even though transistor-based, a passive and reciprocal tuneable inductive behaviour at its terminals over a broad range of biasing conditions and frequencies. Thereby it accommodates more degrees-of-freedom in circuit design and possibilities for interesting applications, e.g., in integrated circuit design for a multitude of relevant applications in sensing and mobile communications. A test board was implemented and measured, confirming the principle-of-operation in agreement with numerical simulations, demonstrating a transistor-based, passive, tuneable, nearly reciprocal inductance over a frequency range larger than a decade.
Pedagogy of the “Not”: Negation, Exodus, and Postdigital Temporal Regimes
Postdigital capitalist time is an incessant acceleration that acts to homogenize time and wed us to the present, to which we have to constantly catch up. While the impulse of this is no doubt economic (the realization of value), it is crucially undergirded by a pedagogical logic wherein we have to perpetually learn and re-learn the latest apps, social media configurations, operating systems, and so on. Political strategies of resistance thus need to be bolstered by an alternative mode of educational life, and I propose a pedagogy of the “not” as one possibility. Such a pedagogy is an act of suspension that sustains a detachment from the present, clearing out oppositions and thereby exposing us to a radical indeterminacy and potentiality that is always untimely. Suspension is the praxis of negation, which means that negation operates by keeping sense indeterminate to meaning and signification. Rather than suppressing, disavowing, or annihilating the stated content, negation retains even that which is negated. While this would appear as a form of exopedagogy, which withdraws from the dialectic of the private/public, I instead argue that it redefines the terms of any dialectic, redefining the very categories exopedagogy withdraws from. Before concluding, I spend some time with Sandy Grande’s important critiques of Eurocentrism and progress in Western critical education, demonstrating how negation as suspension circumvents these errors through its accommodation of—or, better, insistence on—variegated temporalities and forms of life.