7700 MultiFrame Manual
7736CEM Composite Encoder with Monitoring
Revision 1.5
Page - 35
*Grey background indicates un-implemented or un-tested features
7.8.4. Setting the PPM Mode and Ballistics
Bar graphs
This parameter selects one of four industry standard of Peak Program
Meter (PPM) display modes.
When one of these modes is selected, a number of items are set to
adhere with predefined industry standards. The items affected include;
meter attack time, meter decay time, min level displayed, max level
displayed, analog reference (100%) level and, in some instances,
region colouring and phase graph representation. Table 7-1 illustrates
the values set by the standards.
Bar graphs 1 and 2
PPM mode
DIN,
BBC,
Nordic N9,
AES/EBU
Mode
Attack
Time
Decay
Time
Ref.
Level
Min
Level
Max
Level
Peak
Output
Level
Notes
DIN 45 406
(IRT Rec. 3/6)
10 ms
1.5 sec
for
20 dB
6 dBu
-50 dB
5 dB
6 +
headroom
1 dB per div until –10 dB,
logarithmic to bottom -50dB.
Associated DIN phase
correlation scale:
•
both the same => 1 r,
•
only 1 signal => 0 r,
•
both out of phase => -1r.
BBC "IEC 128-10,
type IIa, fast mode
10 ms
2.8 sec
for 7 to 1
8 dBu
1
-12 dB
7
+12 dB
8 +
headroom
# 6 on the scale is the
reference level
Nordic N9
5 ms
1.7 sec
for
20 dB
6 dBu
-42 dB
+12 dB
6 +
headroom
AES/ EBU
1
sample
period
1.5 sec
for
20 dB
User
defined
-60 dB
0 dB
User
defined
100% reading is user
definable.
0 dB corresponds to 0 dB
FS.
Table 7-1: PPM Bar Graph Characteristics
Please Note: The phase correlation scale on the DIN type is different from our other
phase indicators (Sum + Diff and phase bar graphs).
7.8.5. Setting the VU Display Range
Bar graphs
This parameter selects the VU display range when VU modes are
active.
Most VU meters have two possible ranges. These are:
Normal range: +3 to –20dB
Extended range: +3 to –57dB
The bar graphs will be re-scaled to represent the selected range.
When using VU and BBC PPM mode, the VU scale is truncated to
–6dB to match the scaling of BBC mode.
Bar graphs 1 and 2
VU range
Normal
Extended
