GS1574 Data Sheet
+187.5mV
V
= 2.925V
typical
CM
-187.5mV
SDO
SDO
+187.5mV
50
50
V
= 2.925V
typical
CM
-187.5mV
Figure 4-1: Typical Output Voltage Levels
4.3 Programmable Mute Output
For SMPTE 259M inputs, the GS1574 incorporates a programmable threshold
output mute (MCLADJ).
In applications where there are multiple input channels using the GS1574, it is
advantageous to have a programmable mute output to avoid signal crosstalk.
The output of the GS1574 can be muted when the input signal decreases below a
certain input level. This threshold is determined using the input voltage applied to
the MCLADJ pin. The MCLADJ pin may be left unconnected for applications where
output muting is not required.
This feature has been designed for use in applications such as routers where
signal crosstalk and circuit noise cause the equalizer to output erroneous data
when no input signal is present. The use of a Carrier Detect function with a fixed
internal reference does not solve this problem since the signal to noise ratio on the
circuit board could be significantly less than the default signal detection level set by
the on chip reference.
NOTE: MCLADJ is only recommended for data rates up to 360Mb/s. For data rates
above this MCLADJ should be left floating.
4.4 Mute
In addition to the programmable mute output, the GS1574 includes a MUTE input
pin that allows the application interface to mute the serial digital output at any time.
Set the MUTE pin HIGH to mute SDO and SDO.
28854 - 5 May 2007
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GENNUM [ GENNUM CORPORATION ]
