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二、四端口通路器四端口通路器是数字超大规模集成电路,芯片的面积为70mm~2(8.5×8.1),内含39000个器件,用3μNMOS工艺制造。目前它有PLCC(塑封)和CLCC(陶封)两种封装形式。外引脚都是68条。图2是四端口通路器的内部功能框图。图2仅表示了一个端口对,即一收、一发。另一对端口由于对称相同或公用,因此未画入。下面对主要功能块作简单介绍: (一)接收端口 1.输入同步电路每个接收端口有一个PCM码位输入端,(LBW输入端只是测试时供自环所用)。本功能块对输入的码流实现位同步(与QUAP内部的4MHz时钟同步)和帧同步,再经过奇偶校验和串、并交换,使进来的串行码成为平行码输出。 2.接收通道时序器终端接口中所有端口上的输出信号若要进行交
Two-and Four-Port Thru The four-port thru is a digital VLSI chip with an area of 70mm-2 (8.5x8.1) and contains 39,000 devices fabricated in a 3μN MOS process. Currently it has PLCC (plastic seal) and CLCC (ceramic seal) two packages. External pins are 68. Figure 2 is the internal functional block diagram of the four-port circuit breaker. Figure 2 shows only one port pair, a receipt, a hair. The other pair of ports are not drawn because they are symmetrical or common. The following main function block for a brief introduction: (A) the receiving port 1. Input synchronization circuit Each receiving port has a PCM code bit input, (LBW input only for testing from the ring). This function block realizes bit synchronization (4MHz clock synchronization with QUAP) and frame synchronization to the input code stream, and then undergoes parity check and string exchange to make the incoming serial code become parallel code output. 2. Receive Channel Sequencer The output signals on all ports in the terminal interface are forwarded