import numpy as np

def DFT(x):
    """
    Compute the Discrete Fourier Transform (DFT) of the input signal x.
    
    Parameters:
        x (array-like): Input signal
        
    Returns:
        X (array-like): DFT of the input signal
    """
    N = len(x)
    n = np.arange(N)
    k = n.reshape((N, 1))
    e = np.exp(-2j * np.pi * k * n / N)
    X = np.dot(e, x)
    return X

# Example usage:
x = np.array([0, 1, 2, 3])
X = DFT(x)
print("DFT of", x, ":", X)