# How to use stdisp to calculate the power level for a shape pulse

1. Get the known calibrated 90° square (hard) pulse length and power level.
2. type stdisp in topspin and open the shape file you want, (and find the shape pulse length, integral factor (IF), and the total rotation angle from the file contents.)
3. click analysis → integrate shape → input shape pulse length, rotation angle, calibrated 90 hard pulse length, and enter.
4. the results will show the difference Δ of power level, so the shape pulse power level will be set to (Δ + hard pulse power level).
5. (for an adiabatic shape pulse, click analysis → integrate adiabatic shape → input shape pulse length, calibrated 90 hard pulse length, and enter.)

calcplen — calculate new pulse length at a given different power level with known calibrated 90° (hard) pulse length and power level.

calcpowlev — calculate new power level at a given pulse length with known calibrated 90° (hard) pulse length and power level.

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In order to calculate the power level for an non-adiabatic shape pulse:

Using the equation: dB2 – dB1 = Δ = 20*log((pw2*IF)/pw1)         —unit(dB)

pw2 – shape pulse length; pw1 – 90° hard pulse length; IF – integral factor = area of shape pulse/area of square pulse with the same length

[ if it’s 180° rotation with that shape pulse length, it’s power level will be:

dB2 – dB1 = Δ = 20*log(pw2*IF/(2*pw1))

= 20*log(pw2*IF/pw1) + 20log(1/2)

= 20*log(pw2*IF/pw1) – 20*0.3

= 20*log(pw2*IF/pw1) – 6          — unit (dB)   ]

In order to calculate the power level for an adiabatic shape pulse:

use the same equation as the above for inversion pulses and quality /adiabaticity factor Q=5; for decoupling pulses and Q=3, use:

dB2-dB1 = Δ = 20*log(pw2*IF*(5/3)1/2/(2*pw1))                                       — unit (dB)

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Hongwei edited on 02/05/2024