Tektronix WFM5200 Technical Reference page 25

Table 14: Audio bar displays (cont.)
Characteristic
Correlation Meter Speed
Metering Ballistic Types
Peak Program Meter (PPM)
Ballistic Response
True Peak Ballistic Response
WFM5200 Waveform Monitor Specifications and Performance Verification
Performance requirement Reference information
User selectable 1 to 20. Factory default is
set to 8.
Speed 1 averages over 0.04 sec.
Speed 2 averages over 0.04 sec.
Speed 3 averages over 0.08 sec.
Speed 4 averages over 0.12 sec.
Speed 5 averages over 0.28 sec.
Speed 6 averages over 0.52 sec.
Speed 7 averages over 1.0 sec.
Speed 8 averages over 1.5 sec.
Speed 9 averages over 2.0 sec.
Speed 10 averages over 2.5 sec.
Speed 11 averages over 3.0 sec.
Speed 12 averages over 3.5 sec.
Speed 13 averages over 4.0 sec.
Speed 14 averages over 4.5 sec.
Speed 15 averages over 5.0 sec.
Speed 16 averages over 5.5 sec.
Speed 17 averages over 6.0 sec.
Speed 18 averages over 6.5 sec.
Speed 19 averages over 7.0 sec.
Speed 20 averages over 7.5 sec.
The Phase Correlation Meter Speed setting
determines how quickly the meter reacts to
changes in phase relationship. The meter
reading is actually an average of correlation
over time, and this setting determines how
many samples are used to calculate the
average. The instrument uses the fewest
samples when this setting is 1, and the
meter reacts almost instantaneously. The
instrument uses the most samples when the
setting is 20, and the meter reacts much
more slowly. Experiment to find the setting
that best fits your application.
Selectable from true peak, PPM Type 1,
PPM Type 2, and Extended VU.
PPM Type I (IEC Type I, essentially the same
as DIN 45406 and Nordic N-9).
PPM Type II (IEC Type II, the same as IEEE
std. 152-1991).
PPM Type I has a slightly faster attack time
and a faster return time, 1.7 seconds to fall
20 dB as opposed to 2.8 seconds for Type II.
PPM Type II decay characteristics, no attack
delay, factory default ballistic.
Specifications
9