The Endocrine System Essentials. 1  The endocrine system is made up of a network of glands. 2  These glands secrete hormones to regulate many bodily functions, including growth and metabolism. 3  Endocrine diseases are common and usually occur when glands produce an incorrect amount of hormones.
The Fourier transform is called the frequency domain representation of the original signal. The term Fourier transform refers to both the frequency domain representation and the mathematical operation that associates the frequency domain representation to a function of time.
Different from the discrete-time Fourier transform which converts a 1-D signal in time domain to a 1-D complex spectrum in frequency domain, the Z transform converts the 1D signal to a complex function defined over a 2-D complex plane, called z-plane, represented in polar form by radius and angle .