Radio Frequency by Steve Winder and Joe Carr - HTML preview

24.6 Characteristics of UHF terrestrial television systems

24.6.1 World systems

bandwidth

A Number625 Channel 8 5.5
B 625 8 5.0
C 625 8 5.0
D 625 8 6.0
E 625 8 6.0
F 525 6 4.2

A – UK and Eire
B – Eastern Europe
C – Most of Western Europe, Australia, New Zealand D – France
E – Russia and Eastern Europe
F – USA, most of Central and South America, Japan

^ide-band modulation modulation

^sion/soundseparation 1.25 Neg. FM 50+6
+5.5 1.25 Neg. FM 50
+5.5 0.75 Neg. FM 50
+6.5 1.25 Pos. AM 50
+6.5 0.75 Neg. FM 50
+4.5 1.25 Neg. FM 60

24.6.2 European systems

Country

Austria
Belgium
Bulgaria
Cyprus
Czechoslovakia Denmark
Finland
France
Germany
C PAL B PAL No UHF system
C PAL E SECAM No UHF system PAL C PAL D SECAM C PAL

Country

German DR Greece
Holland
Hungary
Iceland
Ireland
Italy
Luxembourg Malta
Monaco
Norway
Poland
Portugal
Romania
Spain
Sweden
Switzerland Turkey
UK
USSR
Yugoslavia C SECAM B PAL C PAL E SECAM No UHF system
A PAL C PAL D SECAM B PAL D SECAM C PAL E SECAM C PAL E PAL C PAL C PAL C PAL No UHF system
A PAL E SECAM B PAL

24.6.3 UK 625-line television system specification

Channel bandwidth 8 MHz Upper sideband (vision signal) 5.5 MHz Lower sideband (vision signal) 1.25 MHz Vision modulation AM negative Sound modulation FM Sound deviation (max.) ±50 kHz Sound pre-emphasis 50µs Sound carrier relative to vision +

carrier
Aspect ratio 4:3 Blanking and black level 76% White level 20% peak Sync. level 100% peak Video bandwidth 5.5 MHz Field frequency Line frequency Field sync. signal

Field sync. and flyback intervals Line period (approx.)
Line syn. pulses (approx.) Line blanking (approx.)
Field sync. pules (broad)
Field sync. pulses (equalizing) Colour subcarrier frequency Burst duration
Burst amplitude
Burst phase
50 Hz
15 625 Hz
5 equalizing then 5

broad pulses,
followed by 5
equalizing pulses in 7.5 line periods

2 × 25 line periods
64µs
4.7µs
12µs
27.3µs
2.3µs
4.43361875 MHz
2.25µs
equal to sync
180^æ ± 45^æ

24.6.4 UK 625-line television system field blanking details

Field sync datum

Field blanking (25 Lines and line blanking)
2.5 Lines 2.5 Lines 2.5 Lines
5 Equalising Field sync 5 Equalising
pulses 5 broad pulses
pulses
End of odd fields Beginning of even fields
Line number 623 624 625 1 2 3 4 5 6 23 100

⁷⁵ Equalising pulses Broad pulses^{27.3 ± 0.1 µs} 27.3 ± 0.2 µs

20
0
End of even fields Line number 311₁₀₀

75
Beginning of odd fields
312 313 314 315 316 317 318 336
Blanking and black level Sync level

Peak white level 20
0

_{Rise times} Field blanking 0.3 ± 0.1 µs (10%
−
90%)
Field sync 0.25 ± 0.05 µs Equalising pulses 0.25 ± 0.05 µs