 video to deal with digitized content in net- work environments. If you are knowledgeable about digitized content as outlined in these two references, then you are well primed for transporting content in digital networks. As a bridge to digital networks and digital content transport here's a list of topics and a little about each you need to know: Analog to digital conversion (A/D) is the process of sampling a continu- ous wave voltage or current signal, and quantifying each sample to PRACTICAL IP AND TELECOM FOR BROADCAST ENGINEERING AND OPERATIONS some precise real number mathematical value within a specific range. There are two steps in A/D conversion-sampling and quantization. A/D converters require power and clocking signals. The output of an A/D converter is always a group of signals, each on a single con- ductor, synchronized to the clocking signal. The number of signals appearing at the output of the A/D is always equal to the quantizing depth or capability of the converter. For example if the converter is said to be an 8-bit converter, its output signal would require at least 10 conductors; one for common or ground, one for clock signal and 8 for each of the signal bits ranging from 1 through 8 or 0 through depending on the preference or convention of the designer. A 12-bit converter would require 14 conductors; a 16-bit converter would require 18 conductors and SO on. The output of an A/D converter is called a parallel digital signal because all the bits appear in parallel timed according to the input clock signal. Digital to analog conversion (D/A) is the reverse of A/D. A parallel digital input signal is converted to an analog output signal. Like its counterpart, the D/A converter requires power and clocking signals to perform its function. Clock signal is a continuous stream of positive and negative going voltage waveform transitions of equal period- icity. Clock signals are derived from highly stable continuous wave oscillators whose natural output is a sine wave. Typically the sine wave is of suffi