Jonny Johansson

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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)
This paper describes the design of a highly integrated ultrasound sensor where the piezoelectric ceramic transducer is used as the carrier for the driver electronics. Intended as one part in a complete portable, battery operated ultrasound sensor system, focus has been to achieve small size and low power consumption. An optimized ASIC driver stage is(More)
We have designed, fabricated and operated a scalable system for applying independently programmable timeindependent, 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)
We have designed, fabricated and tested an XYaddressable 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)
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)
The use of PSpice models for piezoelectric devices and ultrasonic transmission media is of major importance when designing electronics for ultrasonic systems. Today, these models include viscoelastic 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 of(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)
This paper presents a compensation structure to reduce the output common mode current of a rail-to-rail constant gm transconductance stage. The transconductance stage is a differential structure with the input transistors biased in weak inversion. This results in low power consumption and a simple relation between gm and tail currents. The constant gm is(More)