DS2152 and DS2154: 8 MHz System Clock Operation
Tom Spencer, Product Manager, Telecom Products
The DS2152 and DS2154 PCM signals can interface to an 8 MHz system backplane. Typically this application is used to mulitplex four 2.048 MHz PCM streams onto a single 8 MHz PCM stream. To accomplish this, the elastic stores are enabled and placed in the 2.048 MHz System Clock mode. Figure 1 describes a timing scheme in which a single RSYNC is generated for all four framers. Each framer in turn is driven with an 8.192 MHz clock burst of 8 cycles. Each clock burst causes the elastic store to output 1 DS0. This results in a "Byte Interleaved" 8.192 MHz PCM stream as shown in Figure 2.
Figure 1
