I currently got hold of the book "Handbook of MRI Pulse Sequences" and am looking into computing the duration, gradient strength and ramp times for the phase encoding gradient, readout prehasing and the slice prephasing gradients.
Now, every GE pulse sequence diagram that I look at, shows these gradients to be of the same duration i.e. they start and end at the same time during the sequence. Now, going through some of the calculations in the book for a scanner with some maximum gradient strength, slew rate, receiver BW, field of view and the k-space matrix size, I can compute the optimal gradient strengths and the durations for these gradients.
However, the optimal gradients are not the same duration. Does this mean I have made a mistake in my calculations or do they overlap these gradients in the pulse sequence diagrams for convenience?