Thomas Witzel

Small Scale 600W Gradient Power Amplifier

Hello OCRA and Tabletop Community, I would like to introduce the low-cost 4-channel 600 W Gradient Power Amplifier (GPA) for our OCRA Tabletop MRI system. Basically, the GPA converts a voltage input coming for example from the OCRA1 (see blog post from Marcus) into currents to supply gradient coils. The GPA can handle gradient sequences (pulsed…

30 Sep

Transmit-Receive Switch for the OCRA Tabletop MRI system

Hello OCRA and Tabletop Community, In this blog I will share my Transmit-Receive (TR) switch design for our OCRA Tabletop MRI system. As it’s a general design, it also can be used for small RF-power applications in other MRI systems. The TR-switch is used to connect the RF-coil (antenna) to the RF Power-Amplifier (RFPA) in…

27 Nov

OCRA1 – SPI controlled 4 channel 18bit DAC and RF Attenuator

Hello OCRA Community, I would like to introduce you to one of the core elements of our OCRA Tabletop MRI console, the OCRA1. It’s a peripheral printed circuit board (PCB) that extends a Red Pitaya to a basic MRI console. All its components are controlled with the Serial Peripheral Interface (SPI) bus given by the…

05 Nov

The OCRA Project in Magdeburg, Germany

Hello OCRA Community! My name is Marcus Prier and I’m working at the Research Campus STIMULATE of the Otto-von-Guericke University Magdeburg (Germany). I’m a physicist and specialized in MRI RF electronics development. A few years ago, I had a short-term scholar at the Athinoula A. Martinos Center in Boston supervised by Larry Wald in Boston where I…

27 Jul

Porting RP-125 FPGA bitstream features to RP-122

My name’s Vlad Negnevitsky, and I’ve been working on OCRA part-time since mid-2019 on behalf of the MRILab at i3m in Valencia, Spain. I’m not an MRI physicist, and I’ll mainly be discussing the technical side of OCRA. OCRA is a multi-level project, bringing together lots of fun engineering at the electronics/hardware, FPGA firmware, embedded…

23 Jul

Welcome to the OCRA blog!

What started in a little corner of my tiny Boston apartment, and then later advanced with the help of numerous students that shall be listed soon on this page has now become a project bigger than just my hobby, with users and contributors in both Europe and the USA. In order to keep the community…

Author: Thomas Witzel