Chirp as test gradient for MRI gradient system characterization

2 次查看（过去 30 天）
preethi chandrasekarn
回答： Kaashyap Pappu 2020-1-22
Hi ! i wanted to generate gradient pulse for MRI gradient system characterization using chirp,For a chirp function linearly sweeping the frequency range f1 to f2 over a duration T
f0=100hz
f1=10khz
Time duration=80ms
The maximum gradient amplitude is between 20 and 31 mT/m
the instantaneous frequency f is f (t) = f1 + (f2 − f1)t/T
The chirp gradient waveform Gc with amplitude A is
Gc(t) = A sin(2π[f1t + (f2 − f1)t^2/2T])
The slew rate s(t) = dGc/dt = 2πAf (t) cos(2π[f1t + (f2 − f1)t^2/2T])
has an envelope se(t) = 2πAf (t)
The slew-rate-limited chirp gradient waveform,
Gsrlc, for a maximum slew rate, smax, is then calculated as Gsrlc(t) = min{smax/se(t), 1}Gc(t)
Please guide me how to proceed with the code.
Thank you for your valuable time and guidance.Any answers would be great to discuss.

请先登录，再回答此问题。

回答（1 个）

Kaashyap Pappu
Kaashyap Pappu 2020-1-22
A similar question has been addressed here. Modifying the ‘f1’ and ‘f2’ values, and changing the sample rate to accommodate the different frequencies to adhere to Nyquist theorem will probably be a solution.
Hope this helps!

类别

在 Help Center 和 File Exchange 中查找有关 MRI 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by