54200
Users Manual
4-70
IRS17
Description:
The IRS17 test pattern (Insertion-Reference Signal) is generated only for PAL 625 line
systems in the visible part of the TV lines. The IRS17 signal is according to EBU Rec. R26-
1981 (1995 edition) and serves to detect, measure, and correct distortion in TV signals.
Details IRS17:
•
a luminance bar (reference white), amplitude 0.7 V.
•
a 2T sine-squared pulse, Half Amplitude Duration (HAD) 200 ns.
•
a modulated 20T pulse, HAD 2 µs.
•
a 5 step staircase luminance signal, 140 mV per step.
Figure 4-106. IRS17 Test Pattern
The line contents of the IRS17 pattern are identical to the IRS Line 17 signal,
see Figure 4-113.
The IRS17 test pattern can be switched on only for all PAL 625 line systems.
Press the
DIVERSE
key to select in the
Diverse
popup menu
IRS17
.
Remark:
If you select the Crosshatch pattern without color burst the chroma signal in the IRS17 is
also switched off.
Applications:
This signal combination is mainly used as test lines for automatic measurement and
monitoring of TV signals. The luminance bar also serves as amplitude reference for
automatic level control.
The following distortions can be measured using the IRS17 signal:
•
Luminance bar:
distortion, level error, line time waveform, overshoot and rounding.
•
2T pulse:
group delay, amplitude error, pulse distortion, and reflections.
•
20T pulse:
amplitude and delay difference between luminance and chrominance.
•
Staircase luminance signal:
static nonlinearity, amplitude nonlinearity.
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