LMH0056_07 Datasheet, PDF (12/16 Pages) National Semiconductor (TI) – HD/SD SDI Reclocker with 4:1 Input Multiplexer

SD/HD
The SD/HD output indicates whether the LMH0056 is pro-
cessing SD or HD data rates. It may be used to control
another device such as the LMH0002 cable driver. When this
output is high it indicates that the data rate is 270 Mbps (or
143 Mbps). When low, the indicated data rate is 1483 or
1485 Mbps. The SD/HD output is a registered function and is
only valid when the PLL is locked and the Lock Detect output
is high. When the PLL is not locked (the Lock Detect output
is low), the SD/HD output defaults to HD (low). The SD/HD
output is undefined for a short time after lock detect assertion
or de-assertion due to a data rate change on SDI. See Figure
3 for a timing diagram showing the relationship between SDI,
Lock Detect, and SD/HD.
FIGURE 3. SDI, Lock Detect, and SD/HD
20201905
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