US3974519A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for reproducing a PAL color television signal which is recorded on a record carrier and drop out compensation
Assignee: US Philips Corp
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Filing: 1974-06-28
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Granted: 1976-08-10
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Expires: 1994-06-28
Abstract
Abstract A circuit for reproducing recorded PAL TV signals features a pair of mixers that produce signals of opposing phases. Thus the same picture can be repetitively viewed without losing the PAL phase alternation. Drop out compensation can be added.
Inventors
- 👤 Willem van den Bussche
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 00:14
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/87; H04N9/88; H04N9/873; Y; Y10; Y10S; Y10S358/00; Y10S358/907
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
299 words
An apparatus for reproducing a color television signal which is recorded on a record medium and which comprises a first carrier, which is frequency-modulated by the luminance information, and a second carrier, which is modulated by the chrominance information in accordance with the PAL-standard and whose frequency lies between zero and the first-order lower side band of the modulated first carrier, said apparatus comprising a first chrominance circuit including a first mixing circuit, said first mixing circuit having first input means for receiving the modulated second carrier read from the record carrier and a second input means for receiving a first mixing signal which has a frequency which equals the sum of the standard PAL chrominance carrier frequency and the second carrier frequency, and a first output terminal means for providing a first standard PAL-chrominance signal; a second chrominance circuit including a second mixing circuit, said second mixing circuit having first input means for receiving the modulated signal second carrier read from the record carrier and a second input means for receiving a second mixing signal which has a frequency which equals the difference between the standard PAL chrominance carrier frequency and the second carrier frequency, and a second output terminal means for providing a second standard PAL chrominance signal; a first output circuit; a first switching device means for coupling in a first position the first output terminal to said first output circuit and for coupling in a second position the second output terminal to said first output circuit; and a programming device coupled to said first switching device for altering the position of said first switching device at the transition of two successively read out color television signal frames having the same PAL-sequence, whereby the sequence of scanning of the recorded color television signal frames is changed.
Claim 2
Independent Claim
299 words
An apparatus for reproducing a color television signal which is recorded on a record medium and which comprises a first carrier, which is frequency-modulated by the luminance information, and a second carrier, which is modulated by the chrominance information in accordance with the PAL-standard and whose frequency lies between zero and the first-order lower side band of the modulated first carrier, said apparatus comprising a first chrominance circuit including a first mixing circuit, said first mixing circuit having first input means for receiving the modulated second carrier read from the record carrier and a second input means for receiving a first mixing signal which has a frequency which equals the sum of the standard PAL chrominance carrier frequency and the second carrier frequency, and a first output terminal means for providing a first standard PAL-chrominance signal; a second chrominance circuit including a second mixing circuit, said second mixing circuit having first input means for receiving the modulated signal second carrier read from the record carrier and a second input means for receiving a second mixing signal which has a frequency which equals the difference between the standard PAL chrominance carrier frequency and the second carrier frequency, and a second output terminal means for providing a second standard PAL chrominance signal; a first output circuit; a first switching device means for coupling in a first position the first output terminal to said first output circuit and for coupling in a second position the second output terminal to said first output circuit; and a programming device coupled to said first switching device for altering the position of said first switching device at the transition of two successively read out color television signal frames having the same PAL-sequence, whereby the sequence of scanning of the recorded color television signal frames is changed.
Claim 3
Dependent Claim
76 words
An apparatus as claimed in claim 1, wherein said medium comprises a disk-shaped record medium with tangentially arranged tracks which are scanned by a scanning device and which contains an odd number of color television signal frames per full revolution, and wherein the programming device comprises means for providing a switching signal to the switching device for altering its position upon each commanded radial jump of the scanning device over an odd number of track distances.
Claim 4
Dependent Claim
225 words
An apparatus as claimed in claim 1, wherein the first switching device means includes a first and second switch, which are interlocked and which each have a first and a second input and an output, the first and the second input of the first switch receiving the first and second standard PAL chrominance signal respectively, the first and second input of the second switch receiving the second and first standard PAL chrominance signal respectively, the output of the first switch being coupled to the first output circuit, and further comprising a second output circuit coupled to the output of the second switch, a second switching device having a first input coupled to the first output circuit, and a second input coupled to the second output circuit, which second output circuit includes a first delay means for ensuring that the signal applied to the second input of the second switching device is delayed by one line time relative to the signal applied to the first input, and a drop-out detector means for controlling the second switching device which, in the absence of a signal drop-out establishes a connection between the first input of the second switching device and a chrominance output terminal, and upon the occurrence of a drop-out establishes a connection between the second input of said second switching device and said chrominance output terminal.
Claim 5
Dependent Claim
166 words
An apparatus as claimed in claim 1, further comprising a third switch coupled between the output of the first mixing stage and the first output terminal, a fourth switch coupled between the output of the second mixing stage and the second output terminal, which third and fourth switches are interlocked, second and third delay means, a drop-out detector means for controlling said third and fourth switches which in the absence of a drop-out establish a connection between the output of the first and second mixing stage respectively and the first and second output terminal respectively, and upon the occurrence of a signal drop-out establish a connection between the output of said second and third delay means respectively and said first and second output terminal respectively, the two delay means having a delay of one line time and the input of the second delay means being coupled to the second output terminal and the input of the third delay means being coupled to the first output terminal.
Claim 6
Dependent Claim
94 words
An apparatus as claimed in claim 1, further comprising means for generating a first reference-oscillator signal with a frequency equal to the standard PAL chrominance carrier frequency, means for generating a second oscillator signal of a frequency equal to the chrominance carrier frequency, means for mixing said first and second oscillator signals, means for extracting the two first-order mixing products which are symmetrically disposed relative to the standard PAL chrominance carrier frequency, and means for locking the frequency of the second oscillator signal to a pilot signal which is recorded on the record carrier.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-10 | 1980-02-09 | 1980-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-10 | 1984-02-09 | 1984-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-10 | 1988-02-09 | 1988-08-10 | $7700.00 | Window Closed / Lapsed |