Analog signals are ____________ waves that transmit information by altering the characteristics of the waves. Analog signals have two parameters, amplitude and ____________. For example, all sounds—including the human ____________—are analog, traveling to human ears in the form of waves. In contrast, ____________ signals are discrete pulses that are either on or off, representing a series of bits (0s and 1s). This quality allows digital signals to convey information in a binary form that can be interpreted by ____________.