encountered infinite loop

[agentmess]

I’ve recently taken an interest in spatial-spectral selective RF pulses for an application I would like to work on. While trying to learn about this kid of pulse design (my background is almost zero) I stumbled across your MATLAB code designed to simulate different types of pulses. Fantastic work, and potentially very helpful!

I’ve got it up and running, however when I change the B0 to 7T (70000G) two things happen – either I get ‘no good fs’ or if I relax the ‘df’ parameter it seems to get stuck in an infinite while look somewhere in the ss_alias function:

LN 89: if (max(df(1:2:end)) >= fs) % there is one band longer than bandwidth, impossible to design such filter

Given your experience, I was wondering if you maybe had a fast explanation for why this might be happening – and to go a step further, are these tools suitable for pulse design at 7T (max B1 ~18uT, max grad ~40mT/m, max slew 200mT/m – but we also have an 8channel multi transmit system…)

I would appreciate any insights if you guys have the time.

Best Regards,

A. Bhogal, Ph.D.