| 摘要 |
<p>Digital signals are multiplexed in tdm (time division multiplex) frames each consisting of an integral number of sub-frames each consisting of an integral number of sub-sub-frames, whereby, the tdm frame, sub-frame, and sub-sub-frame periods (respectively 125, 5, and 5/32) microseconds) are harmonically related. The signals are switched in a hierarchy of time switches (50, 60, 66) which are operated sequentally and cylindrically with frame periods corresponding to respective ones of these harmonically related periods, whereby the switches switch services at respective harmonically related bandwidths. The harmonic tdm frame structure and the hierarchical switch arrangement combine to facilitate the switching of many services with various bandwidths using relatively small switches.</p> |
