GB1207442A - Apparatus for cross-fading between two television signals - Google Patents
Apparatus for cross-fading between two television signalsInfo
- Publication number
- GB1207442A GB1207442A GB70468A GB70468A GB1207442A GB 1207442 A GB1207442 A GB 1207442A GB 70468 A GB70468 A GB 70468A GB 70468 A GB70468 A GB 70468A GB 1207442 A GB1207442 A GB 1207442A
- Authority
- GB
- United Kingdom
- Prior art keywords
- signal
- synchronizing
- colour
- amplitude
- pulses
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000005562 fading Methods 0.000 title abstract 3
- 208000019300 CLIPPERS Diseases 0.000 abstract 1
- 208000021930 chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids Diseases 0.000 abstract 1
- 238000007493 shaping process Methods 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/222—Studio circuitry; Studio devices; Studio equipment
- H04N5/262—Studio circuits, e.g. for mixing, switching-over, change of character of image, other special effects ; Cameras specially adapted for the electronic generation of special effects
- H04N5/265—Mixing
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Processing Of Color Television Signals (AREA)
- Studio Circuits (AREA)
Abstract
1,207,442. Television. FERNSEH G.m.b.H. 4 Jan., 1968 [4 Jan., 1967], No. 704/68. Heading H4F. Apparatus for cross-fading between two television signals, preferably two colour television signals FBASI and FBASII, Fig. 1, comprises an electronic change-over switch 3, the output of which is applied directly and via a device 7 for extracting the synchronizing information, including the colour synchronizing signals i.e. bursts, to the two inputs of a cross-fader device 5 which is so controlled that as the amplitude of the applied television signal (picture signal component and synchronizing information) is varied between zero and the standard level the amplitude of the synchronizing information is correspondingly but oppositely varied between the standard level and zero, so that during cross-fading when the amplitude of the picture signal component of the first television signal is reduced from a standard level to zero, the amplitude of the synchronizing information remains constant, and after changeover (preferably during the period of a vertical synchronizing impulse) when the synchronizing information of the first is changed for that of the second signal and when the amplitude of the picture signal component of the second signal is increased from zero to the standard level, the amplitude of the synchronizing information is again maintained constant. Cross-fader device 5 comprises two adjustable amplifier stages, of which the outputs are connected in parallel, gain control being automatically effected, by means of a control voltage, between unity and zero in such a manner that the sum of relative gains is constant and equal to unity. Two embodiments for deriving the synchronizing information from a colour television signal are described. In the first embodiment, Fig. 2, the synchronizing information comprising the synchronizing signal and the colour synchronizing signal i.e. burst, of the colour television signal FBASI or FBASII at input 11 are gated out by means of gating impulses applied to gate 12. These impulses are derived by suppressing the chrominance component of the colour television signal in trap 14 comprising a low-pass filter, separating the synchronizing signal in an amplitude separator 15, deriving therefrom the horizontal synchronizing pulses in stage 16, advancing these pulses in time in stage 17 so that their leading edges appear somewhat earlier than the leading edges of the horizontal synchronizing pulses, and shaping these pulses in shaper 18 so that their trailing edges occur later than the ends of the colour synchronizing signals. To these pulses is then added in OR gate 19 the equalizing impulses and the vertical synchronizing signal from separator 15. In the second embodiment, Fig. 3, the colour television signal is first separated in frequency into the luminance signal and the chrominance signal in cross-over filter 32 (a combination of high-pass and low-pass filters). From the luminance signal the synchronizing signal S is separated in clipper 33 and from this signal gating pulses are derived in device 34 which are used to separate the colour bursts from the chrominance signal in gating stage 35. The complete synchronizing information is thus obtained from adding stage 36 and applied to the input 8 of the fader device 5 of Fig. 1.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE1967F0051168 DE1296171B (en) | 1967-01-04 | 1967-01-04 | Method for fading between two television signals |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1207442A true GB1207442A (en) | 1970-09-30 |
Family
ID=7104393
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB70468A Expired GB1207442A (en) | 1967-01-04 | 1968-01-04 | Apparatus for cross-fading between two television signals |
Country Status (3)
Country | Link |
---|---|
DE (1) | DE1296171B (en) |
GB (1) | GB1207442A (en) |
NL (1) | NL6800054A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2179269A1 (en) * | 1972-04-17 | 1973-11-16 | Rca Corp | |
FR2595893A1 (en) * | 1986-03-17 | 1987-09-18 | Jocelyn Bertignon | Apparatus for mixing video signals |
-
1967
- 1967-01-04 DE DE1967F0051168 patent/DE1296171B/en not_active Withdrawn
-
1968
- 1968-01-03 NL NL6800054A patent/NL6800054A/xx unknown
- 1968-01-04 GB GB70468A patent/GB1207442A/en not_active Expired
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2179269A1 (en) * | 1972-04-17 | 1973-11-16 | Rca Corp | |
FR2595893A1 (en) * | 1986-03-17 | 1987-09-18 | Jocelyn Bertignon | Apparatus for mixing video signals |
Also Published As
Publication number | Publication date |
---|---|
NL6800054A (en) | 1968-07-05 |
DE1296171B (en) | 1969-05-29 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PCNP | Patent ceased through non-payment of renewal fee |