EP0042680A2
Expired / Lapsed
EP
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A viewfinder for a television camera
Assignee: Link Electronics Ltd
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Filing: 1981-06-03
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Granted: —
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Expires: 2001-06-03
Abstract
Abstract The screen (1) of a viewfinder of a television camera has a horizontally movable vertical cursor (6) and a vertically movable horizontal cursor (7). Knobs are provided for manipulation by the television camera operator to move the cursors (6,7). Further, there are provided fixed upper and lower horizontal lines (2,3), situated respectively adjacent to the top and bottoms of screen (1) and fixed vertical lines (4,5) situated respectively adjacent to the left-hand and right-hand sides of the screen (1). The generators for the cursors and lines rely upon the availability of pulses produced from a synchronising pulse generator IC located within the video processing card within the camera.
Inventors
- 👤 John Peter Kinch
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 08:33
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/60; H04N23/63
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
28 words
A viewfinder for a television camera characterised by generating means for generating a horizontal line (7) movable to any desired position on the screen (1) of the viewfinder.
Claim 2
Dependent Claim
28 words
A viewfinder for a television camera characterised by generating means for generating a horizontal line (7) movable to any desired position on the screen (1) of the viewfinder.
Claim 3
Dependent Claim
29 words
A viewfinder according to claim 1 characterised by second generating means for generating a vertical line (6) movable to any desired position on the screen (1) of the viewfinder.
Claim 4
Dependent Claim
57 words
A viewfinder according to claim 2 characterised by third generating means for generating fixed horizontal lines (2, 3) positioned at the top and bottom respectively of the screen (1) of the viewfinder and fourth generating means for generating vertical lines (4, 5) positioned at the left and right-hand sides respectively of the screen (1) of the viewfinder.
Claim 5
Dependent Claim
108 words
A viewfinder according to any of claims 1 to 3, characterised in that the generating means for generating a movable horizontal line comprises a field rate saw tooth generator (13) which receive the field drive, voltage generating means which generates a voltage signal representative of the height on the screen (1) at which it is desired that the horizontal line should be produced, a comparator (S21) which receive the outputs of the field rate saw tooth generator (13) and the voltage generating means and produces an output when they are identical and signal generating means responsive to the output of the comparator (S21) to provide the horizontal line.
Claim 6
Dependent Claim
23 words
A viewfinder according to claim 4, characterised in that the signal generating means comprises a counter (S22) arranged to generate one horizontal line.
Claim 7
Dependent Claim
83 words
A viewfinder according to claim 2 or claim 3, characterised in that the second generating means comprises a line rate saw tooth generator (10) which receives the line drive signal, voltage generating means arranged which generates a voltage corresponding to the desired distance between the vertical line and one side of the screen (1) a comparator (S18b) which compares the outputs of the line rate saw tooth generator (10) and the voltage generating means and produces an output when their potentials are equal.
Claim 8
Dependent Claim
30 words
A viewfinder according to claim 3, characterised in that the third generating means comprises a counter (S2) which counts line drive pulses occurring after the trailing edge of field drive.
Claim 9
Dependent Claim
33 words
A viewfinder according to claim 3 or claim 7, characterised in that the third generation means comprises a counter (S6) which is clocked by mixed cathode blanking and re-set by mixed system blanking.
Claim 10
Dependent Claim
38 words
A viewfinder according to any of claims 3, 7 and 8, characterised in that the fourth generating means comprises a first differentiating circuit (Rl, Cl) and a second differentiating circuit (R2, C2) which differentiate the mixed system blanking.
Claim 11
Dependent Claim
99 words
A viewfinder according to any of claims 1 to 9, characterised by a zoom angle indicator which generates a mark occurring along the upper horizontal line (2), its distance from one end of the upper horizontal line (2) being indicative of the zoom angle, the zoom angle indicator comprises voltage generating means which generates a voltage representative of the zoom angle and a comparator (Sl8a) which compares the output of a line rate saw tooth generator (10) with the output of the further voltage generating means and produces an output signal when the voltages of its inputs are similar.
References Cited (Backward Citations)
No citation records indexed.
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