Tektronix 070-8811-08 - Manual (Page 68)

Reference
764 Digital Audio Monitor User Manual 53
The De-emphasis Submenu
The De-emphasis submenu, shown in Table 3, lets you select the
appropriate de-emphasis for each of the four input channels. Enter
the De-emphasis submenu from the TOP menu level by scrolling the
highlight to the De-emphasis item and pressing a soft button. Then
scroll the highlight to the desired channel. The four submenu items
are identical, except for the affected channel.
Table 3: De-emphasis submenu
Item Choices Factory setting
БББББББ
ББББББ Б
ББББББ Б
БББББББ
Channel #
(Where # = 1, 2, 3, or 4)
БББББББ
ББББББ Б
ББББББ Б
БББББББ
NONE
AUTO
CCITT J.17
50/15
ББББББББ
БББББББ Б
Б ББББББ Б
ББББББББ
NONE
Selecting either CCITT J.17 or 50/15 will force that type of
de-emphasis. When AUTO is selected, the 764 will apply the
appropriate de-emphasis if either CCITT J.17 or 50/15 emphasis is
indicated in the channel status data of the digital input signal.
If you choose de-emphasis, please be aware that — although the 764
will continue to use raw input data when reporting MUTEs and
CLIPs — the level meters and session statistics will measure and
report levels in the de-emphasized signal. Because de-emphasis
attenuates the higher frequencies of a signal, selecting de-emphasis
may result in meter readings and true peak statistics that understate
the actual signal levels.
When any type of de-emphasis has been selected, it is indicated by a
“flag” on the display above the meter pair, as shown in Figure 34. In
the configuration pictured, de-emphasis has been selected for input
channels 1, 2, and 3 — but not for channel 4. (If de-emphasis was
also not selected for channel 3, the “De-emp” flag would not appear
above the right-hand meter pair.)