In trapezoidal control, when the system moves to the next step, the BEMF of the floating phase specific to the new step is affected by the commutation noise. It is then necessary to avoid capturing that sequence, as it can trigger a false zero-cross point.
This is called blanking time and it must be set based on the speed of the motor. For example, if a blanking time is good for low speeds in a high-speed scenario, the blanking time might be more than enough and the zero cross is not captured. It is calculated by using half of the previous value utilized in the thirty-degree timing.