Patent EP0478024A1 successfully refreshed from Google Patents.
EP0478024A1
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EP
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Signal transient improvement device
Assignee: Koninklijke Philips NV
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Filing: 1991-08-16
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Granted: —
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Expires: 2011-08-16
Abstract
Abstract A signal transient improvement device comprises a delay circuit (1-13) receiving an input signal (C) and having an output supplying an output signal which is undelayed, delayed by a controllable amount or advanced by a controllable amount with respect to the input signal when delayed by a predetermined amount (T3), and a control circuit (15-23) for controlling the delay circuit (1-13). The control circuit (15-23) calculates the second derivative of the input signal (C) to obtain a control signal, the sign of which indicates whether the input signal is to be undelayed, delayed or advanced, while the amplitude of the control signal indicates the amount by which the input signal is to be delayed or advanced.
Inventors
- 👤 Laurens Doornhein
- 👤 Jeroen Maria Kettenis
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 18:31
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/14; H04N5/20; H04N5/205; H04N5/208; H04N5/142; H04N9/00; H04N9/64; H04N9/646
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
182 words
Signal transient improvement device having an input for receiving an input signal with smooth transitions and an output for supplying an output signal with sharpened transitions, comprising: delay means having an input coupled to said device input, a control signal input, and an output for furnishing versions of said input signal to said device output which are undelayed, advanced by a controllable amount or delayed by a controllable amount with respect to said input signal when delayed by a predetermined amount; and control means having a control signal output for applying a control signal to said control signal input, and including differentiating means coupled to receive a signal informing about said input signal for obtaining a second derivative of said informing signal, an output of said differentiating means being coupled to said control signal output, a sign of said control signal controlling whether said input signal is to be undelayed, advanced or delayed by said delay means, while an amplitude of said control signal controls the amount by which said video signal is to be delayed or advanced by said delay means.
Claim 2
Dependent Claim
182 words
Signal transient improvement device having an input for receiving an input signal with smooth transitions and an output for supplying an output signal with sharpened transitions, comprising: delay means having an input coupled to said device input, a control signal input, and an output for furnishing versions of said input signal to said device output which are undelayed, advanced by a controllable amount or delayed by a controllable amount with respect to said input signal when delayed by a predetermined amount; and control means having a control signal output for applying a control signal to said control signal input, and including differentiating means coupled to receive a signal informing about said input signal for obtaining a second derivative of said informing signal, an output of said differentiating means being coupled to said control signal output, a sign of said control signal controlling whether said input signal is to be undelayed, advanced or delayed by said delay means, while an amplitude of said control signal controls the amount by which said video signal is to be delayed or advanced by said delay means.
Claim 3
Dependent Claim
37 words
Signal transient improvement device as claimed in Claim 1, wherein said control means further include a series arrangement of an amplifier and a limiter arranged between said output of said differentiating means and said control signal output.
Claim 4
Dependent Claim
52 words
Signal transient improvement device as claimed in Claim 1, wherein said control means further include a divider having a dividend input coupled to said output of said second differential means, a divisor input coupled to receive a first derivative of said informing signal, and an output coupled to said control signal output.
Claim 5
Dependent Claim
52 words
Signal transient improvement device as claimed in Claim 1, 2 or 3, wherein said delay means comprise a delay line, and a mixing circuit having a first and a second input coupled to an input and an output of delay line, respectively, and a control input coupled to said control signal output.
Claim 6
Dependent Claim
57 words
Signal transient improvement device as claimed in Claim 1, 2 or 3, wherein said delay means comprise a delay line having a plurality of taps, first and second multiplexers each selectively coupling one of the taps to respective multiplexer outputs, and an interpolator coupled to said multiplexer outputs and having an output coupled to said device output.
Claim 7
Dependent Claim
37 words
Signal transient improvement device as claimed in Claim 1, wherein said differentiating means include a cascade coupling of a first differentiator, an absolute value former, and a second differentiator supplying said second derivative of said informing signal.
Claim 8
Dependent Claim
44 words
Signal transient improvement device as claimed in Claim 6, wherein said control means further include a correction circuit for dynamically limiting said second derivative in dependence upon a zero crossing in a first derivative furnished by said first differentiator, to obtain said control signal.
Claim 9
Dependent Claim
80 words
Signal transient improvement device as claimed in Claim 7, wherein said correction circuit includes means coupled to said first differentiator for furnishing a zero-crossing signal in response to a zero-crossing in said first derivative; shift-register means for serially receiving said zero-crossing signal; decoding means coupled to parallel outputs of said shift register means for obtaining limit values; and limiting means coupled to said second differentiator and said decoding means to limit said second derivative in dependence upon said limit values.
References Cited (Backward Citations)
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