Multiplexing Systems for Pulse-Code-Modulated Hierarchial Networks

Various synchronization systems which function to multiplex lower speed pulse-code-modulated (PCM) signals into a high-speed signal and to drop each lower signal from the highspeed PCM signal, are considered from a practical viewpoint for a useful PCM hierarchial network, and a suitable evaluation basis for such systems is introduced. Three new stuff-synchronization methods are proposed and designed. A severly reliable bit synchronization function necessary for bit multiplexing can be provided by using a quartz crystal resonant circuit. Relations between the system parameters and transmission performance, such as framing time and stuffing error rate, especially stuff-jitter response for coded frequency-division-multiplex (FDM) signal, are analyzed, and the design technique has been established. The test equipments operated perfectly to verify the expected performances. The results suggest these systems are two or four times as advantageous as usual systems on the evaluation basis.