Jonny Johansson

Learn More
—A performance evaluation of a level-crossing analog-to-digital converter (ADC) is presented. It is shown that its signal-to-noise ratio (SNR) does not depend on the input-signal amplitude, which results in an almost-flat SNR for amplitudes that fall into the Nyquist criteria for irregular sampling. The influence of the reconstruction procedure on SNR is(More)
—We have designed, fabricated and tested an XY-addressable readout architecture for superconducting flux qubits in an integrated circuit designed to enable adiabatic quantum optimization algorithms. The readout architecture for an N-qubit system comprises N hysteretic dc SQUIDs and N rf SQUID latches controlled with 2 √ N +2 wires. The latching elements are(More)
– The use of PSpice models for piezoe-lectric devices and ultrasonic transmission media is of major importance when designing electronics for ultrasonic systems. Today, these models include vis-coelastic loss but disregard loss due to diffraction, i.e. beam spreading. This paper presents a method for the inclusion of diffraction loss in PSpice simulations(More)
— We have designed, fabricated and operated a scal-able system for applying independently programmable time-independent, and limited time-dependent flux biases to control superconducting devices in an integrated circuit. Here we report on the operation of a system designed to supply 64 flux biases to devices in a circuit designed to be a unit cell for a(More)
Equivalent circuits for piezoelectric devices and ultrasonic transmission media can be used to cosimulate electronics and ultrasound parts in simulators originally intended for electronics. To achieve efficient system-level optimization, it is important to simulate correct, absolute amplitude of the ultrasound signal in the system, as this determines the(More)
A bridge rectifier based on the cross-connected NMOS-PMOS bridge that avoids the inherent degradation of power conversion efficiency for increasing input levels is presented. Instead of PMOS switches, the proposed rectifier uses diode-connected MOS transistors with static threshold cancellation and minimised diode reverse leakage. With a simple and power(More)