PDH allows transmission of data streams that are nominally running at the same rate, but allowing some variation on the speed around a nominal rate. By analogy, any two watches are nominally running at the same rate, clocking up 60 seconds every minute.

2023年1月11日 · PDH systems employ a technique known as bit interleaving to combine multiple lower-speed data channels into a single higher-speed channel. This process involves alternating the placement of bits from each lower-speed channel into the higher-speed stream, effectively interleaving them to maintain a steady flow of data.

PDH (Plesiochronous Digital Hierarchy) and SDH (Synchronous Digital Hierarchy) are both digital transmission technologies used in telecommunications to transport voice and data signals over high-capacity communication links.

2024年10月17日 · PDH的各速率等级称为一次群、二次群...五次群，将数字信号以固定的速率进行传输。 简单来说，就是PDH规定了一系列大小不同的容器（次群）来容纳不同数量的信号，可以满足不同业务需求。

PDH（Plesiochronous Digital Hierarchy）是一种传输等级体系，用于在数字通信网络中传输语音和数据。 PDH的主要目标是将 语音和数据 转换为数字信号，并以固定的速率进行传输。

2024年11月4日 · PDH follows a hierarchical multiplexing structure. In Europe, it begins at 2 Mbps, which is then multiplexed into 8 Mbps, 34 Mbps, and 140 Mbps levels, while the North American hierarchy starts at 1.5 Mbps (T1), progressing to 6 Mbps (T2), 45 …

2025年2月24日 · PDH的各速率等级称为一次群、二次群…五次群，将 数字信号 以固定的速率进行传输。 简单来说，就是PDH规定了一系列大小不同的 容器 （次群）来容纳不同数量的信号，可以满足不同业务需求。

2019年8月26日 · PDH clocks work very close, but not at exactly the right time with each other so that during transmission times, signal arrival times may vary because transmission speeds are directly related to the clock frequency. PDH means Plesiochronous digital hierarchy and SDH means synchronous digital hierarchy.

2024年4月21日 · What is PDH? PDH called Parallel Data Highway, is a quasi-synchronous transmission technology based on digital transmission. PDH is a synchronous TDM …

PDH technology allow successive multiplexing of a signal from 2 M – 8 M, from 8 M – 34 M, from 34 M – 140 M and finally 140 M – 565 M systems. There also existed “jump” or “skip” muxes that would allow multiplexing of 16 2 M signals into a 34 M signal without the intermediate 8 M level.