2.5.5. Signal Integral

The signal integral "Ix" is calculated with Equation (14) and of the time resolved data from the whole signal y(t) recorded starting at the injection phase (t0 = 0 s), till the end of the packing phase (tn = 11 s). The integral is related to the energy stored in the system and can differ on the measured quantity. When the integral is calculated from the pressure signals, it provides the approximate value of energy stored in the polymer from the melting, compression, and injection of the molten polymer in the cavity.

$$\mathbf{I}\_{\mathbf{x}} = \int\_{0}^{\mathbf{T}} \mathbf{y}(\mathbf{t})d\mathbf{t} \tag{14}$$

T: end time of signal during (time = 11 s).

#### 2.5.6. Signal Power

The power of a signal x, "SPx" is given as the sum of the absolute squares of the time-domain samples of the signals divided by the signal length. Similar to the integral, signal power relates to the energy of the system for all the recorded frequencies of the signal.

$$\text{SP}\_{\mathbf{x}} = \lim\_{\mathbf{T} \to \infty} \frac{1}{\mathbf{T}} \int\_{0}^{\mathbf{T}} |\mathbf{y}(\mathbf{t})|^{2} \mathbf{d}\mathbf{t} \tag{15}$$

T: end time of signal during (time = 11 s).
