Patent EP0177987A1 successfully refreshed from Google Patents.
EP0177987A1
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EP
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Field-frequency doubling circuit
Assignee: Koninklijke Philips NV
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Filing: 1985-08-30
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Granted: —
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Expires: 2005-08-30
Abstract
Abstract By providing in a field-frequency doubling circuit comprising a converter circuit (3) of an A, A, B, B, type, an interpolation circuit (31) which combines in an appropriate manner the information of two subjacent lines of the first field of a picture of the television signal to be converted and the second field of a picture of the television signal to be converted, line flicker can be prevented from occurring without it being necessary to provide a movement detector and a change-over switch for an A, B, A, B-type conversion.
Inventors
- 👤 Franciscus Wilhelmus Petrus Vreeswijk
- 👤 Sing Liong Tan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-10 02:23
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/04; H04N5/06; H04N7/00; H04N7/01; H04N7/0127; H04N7/0132
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
261 words
A field-frequency doubling circuit, comprising a converter circuit (3) for converting an interlaced television signal to be converted having a picture frequency of n pictures per seond and a field frequency of 2n fields per second, into a converted television signal having a field frequency of 4n fields per second, the fields of the converted television signal having substantially the same number of lines as the fields of the television signal to be converted and every two consective fields of the television signal converted by the converter circuit being equal to each other, and comprising, coupled to an output of the converter circuit an interpolation circuit (31) for adding together information from some lines of the converted television signal in each line period of the converted television signal, characterized in that the interpolation circuit comprises a change-over switch (57) for interpolating each group of four fields of the converted television signal during the first and third fields of this group between a line of the converted television signal corresponding to a line of a first field of a picture of the television signal to be converted and a line corresponding to a subjacent line of the second field of a picture of the television signal to be converted, and during the second and fourth fields of this group between a line of the converted television signal corresponding to a line of the first field and a line of the converted television signal corresponding to a superjacent line of the second field of a picture of the television signal to be converted.
Claim 2
Dependent Claim
261 words
A field-frequency doubling circuit, comprising a converter circuit (3) for converting an interlaced television signal to be converted having a picture frequency of n pictures per seond and a field frequency of 2n fields per second, into a converted television signal having a field frequency of 4n fields per second, the fields of the converted television signal having substantially the same number of lines as the fields of the television signal to be converted and every two consective fields of the television signal converted by the converter circuit being equal to each other, and comprising, coupled to an output of the converter circuit an interpolation circuit (31) for adding together information from some lines of the converted television signal in each line period of the converted television signal, characterized in that the interpolation circuit comprises a change-over switch (57) for interpolating each group of four fields of the converted television signal during the first and third fields of this group between a line of the converted television signal corresponding to a line of a first field of a picture of the television signal to be converted and a line corresponding to a subjacent line of the second field of a picture of the television signal to be converted, and during the second and fourth fields of this group between a line of the converted television signal corresponding to a line of the first field and a line of the converted television signal corresponding to a superjacent line of the second field of a picture of the television signal to be converted.
Claim 3
Dependent Claim
96 words
A field-frequency doubling circuit as claimed in claim 1, characterized in that the field interpolation circuit (31) comprises a series arrangement of a delay line (35) producing a delay of two field periods minus a line period of the converted television signal and a delay line (53) producing a delay of one line period of the converted television signal and a change-over switch (57) with which alternatingly a sum of an input signal (at 29) of the interpolation circuit and an output signal (at 47, 51) of one of the delay lines is obtained (39, 43).
References Cited (Backward Citations)
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