US4754340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of reproducing a chrominance signal from a previously low-range-converted chrominance signal using comb filtering and sampling
Assignee: Panasonic Holdings Corp
•
Filing: 1984-10-30
•
Granted: 1988-06-28
•
Expires: 2004-10-30
Abstract
Abstract A low-range-converted chrominance signal is demodulated into two color difference signals. The two color difference signals are each filtered by a comb filter to eliminate undesired components. The two color difference signals, having been filtered, are modulated to obtain a carrier chrominance signal having a prescribed carrier frequency. To be suitable for digital signal processing, the low-range-converted chrominance signal is sampled at a first frequency which is an integral multiple of a low-range-converted carrier frequency of the low-range-converted chrominance signal when being demodulated. The two color difference signals are sampled at a second frequency which is an integral multiple of the prescribed carrier frequency of the carrier chrominance signal.
Inventors
- 👤 Yukio Nakagawa
- 👤 Masao Tomita
- 👤 Tokikazu Matsumoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:57
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/79; H04N9/87; H04N9/8707; H04N9/80; H04N9/82; H04N9/83; H04N9/831
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
153 words
A method of reproducing a carrier chrominance signal with a carrier having a prescribed carrier frequency from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency, comprising the steps of: demodulating said low-range-converted chrominance signal to obtain two color difference signals; filtering said two color difference signals for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively; sampling and holding said two color difference signals after they have been filtered at a predetermined sampling frequency to eliminate high frequency components having frequencies outside of a frequency range of said two color difference signals; and modulating said two color difference signals after they have been filtered so as to obtain said carrier chrominance signal.
Claim 2
Independent Claim
153 words
A method of reproducing a carrier chrominance signal with a carrier having a prescribed carrier frequency from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency, comprising the steps of: demodulating said low-range-converted chrominance signal to obtain two color difference signals; filtering said two color difference signals for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively; sampling and holding said two color difference signals after they have been filtered at a predetermined sampling frequency to eliminate high frequency components having frequencies outside of a frequency range of said two color difference signals; and modulating said two color difference signals after they have been filtered so as to obtain said carrier chrominance signal.
Claim 3
Dependent Claim
77 words
A method according to claim 1, wherein said demodulating step comprises the steps of: multiplying said low-range-converted chrominance signal by a first oscillation signal having said low-range-converted carrier frequency to obtain one of said two color difference signals; and multiplying said low-range-converted chrominance signal by a second oscillation signal having said low-range-converted carrier frequency and a phase shifted by 90° from that of said first oscillation signal to obtain the other of said two color difference signals.
Claim 4
Dependent Claim
100 words
A method according to claim 1, wherein said modulating step comprises the steps of: multiplying one of said two color difference signals after they have been filtered by a first oscillation signal having said prescribed carrier frequency to obtain a first modulated signal; multiplying the other of said two color difference signals after they have been filtered by a second oscillation signal having said prescribed carrier frequency and a phase shifted by 90° from that of said first oscillation signal to obtain a second modulated signal; and mixing said first and second modulated signals to obtain said carrier chrominace signal.
Claim 5
Independent Claim
203 words
A method of reproducing a carrier chrominance signal with a carrier having a prescribed carrier frequency f SC from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency f C , comprising the steps of: sampling said low-range-converted chrominance signal at a frequency nf C to obtain a sampled low-range-converted chrominance signal, where n is an integer; decoding said sampled low-range-converted chrominance signal using an oscillation signal having said frequency f C and a phase which has a predetermined relationship to that of the carrier of said low-range-converted chrominance signal to obtain two color difference signals; filtering said two color difference signals for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively; sampling said two color difference signals after they have been filtered at a frequency mf SC to obtain two sampled color difference signals, where m is an integer; and encoding said two sampled color difference signals using an oscillation signal having said frequency f SC to obtain said carrier chrominance signal.
Claim 6
Independent Claim
203 words
A method of reproducing a carrier chrominance signal with a carrier having a prescribed carrier frequency f SC from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency f C , comprising the steps of: sampling said low-range-converted chrominance signal at a frequency nf C to obtain a sampled low-range-converted chrominance signal, where n is an integer; decoding said sampled low-range-converted chrominance signal using an oscillation signal having said frequency f C and a phase which has a predetermined relationship to that of the carrier of said low-range-converted chrominance signal to obtain two color difference signals; filtering said two color difference signals for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively; sampling said two color difference signals after they have been filtered at a frequency mf SC to obtain two sampled color difference signals, where m is an integer; and encoding said two sampled color difference signals using an oscillation signal having said frequency f SC to obtain said carrier chrominance signal.
Claim 7
Dependent Claim
77 words
A method according to claim 4, wherein said oscillation signal having said frequency nf C is produced by the steps of: extracting a burst signal from one of said two color difference signals; producing a DC signal corresponding to a level of said burst signal from said burst signal; and producing a voltage-controlled oscillation signal whose frequency is proportional to said DC signal, said voltage-controlled oscillation signal being said oscillation signal having said frequency nf C .
Claim 8
Independent Claim
230 words
A method of reproducing a carrier chrominance signal with a carrier having a prescribed carrier frequency f SC from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency f C , comprising the steps of: sampling said low-range-converted chrominance signal at a sampling frequency 4f C to obtain a sampled low-range-converted chrominance signal; inverting said sampled low-range-converted chrominance signal at cycles of 2f C to obtain an alternately inverting low-range-converted chrominance signal which alternately inverts at intervals of 1/(2f C ); sampling said alternately inverting low-range-converted chrominance signal with a first clock signal having a frequency 2f C and a second clock signal having said frequency 2f C and a phase shifted by 180° from that of said first clock signal to obtain two color difference signals; filtering said two color difference signals for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively; sampling said two color difference signals after they have been filtered at a sampling frequency 4f SC to obtain two sampled color difference signals; and encoding said sampled two color difference signals using an oscillation signal having said frequency f SC to obtain said carrier chrominance signal.
Claim 9
Independent Claim
230 words
A method of reproducing a carrier chrominance signal with a carrier having a prescribed carrier frequency f SC from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency f C , comprising the steps of: sampling said low-range-converted chrominance signal at a sampling frequency 4f C to obtain a sampled low-range-converted chrominance signal; inverting said sampled low-range-converted chrominance signal at cycles of 2f C to obtain an alternately inverting low-range-converted chrominance signal which alternately inverts at intervals of 1/(2f C ); sampling said alternately inverting low-range-converted chrominance signal with a first clock signal having a frequency 2f C and a second clock signal having said frequency 2f C and a phase shifted by 180° from that of said first clock signal to obtain two color difference signals; filtering said two color difference signals for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively; sampling said two color difference signals after they have been filtered at a sampling frequency 4f SC to obtain two sampled color difference signals; and encoding said sampled two color difference signals using an oscillation signal having said frequency f SC to obtain said carrier chrominance signal.
Claim 10
Dependent Claim
46 words
A method according to claim 6, further comprising a step, between said sampling step for obtaining said two color difference signals and said filtering step, of interpolating said two color difference signals to obtain two color difference signals each having a sampled frequency 4f C .
Claim 11
Independent Claim
285 words
A method of reproducing a carrier chrominance signal with a carrier having a prescribed carrier frequency f SC from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency f C , comprising the steps of: sampling said low-range-converted chrominance signal at a sample frequency 4f C to obtain a sampled low-range-converted chrominance signal; inverting said sampled low-range-converted chrominance signal at cycles of 2f C to obtain an alternately inverting low-range-converted chrominance signal which alternately inverts at intervals of 1/(2f C ); sampling and holding said alternately inverting low-range-converted chrominance signals with a first clock signal having a frequency 2f C and a second clock signal having said frequency 2f C and a phase shifted by 180° from that of said first clock signal to obtain two color difference signals each having a sampled frequency 2f C ; sampling the sampled and held two color difference signals each having said sampled frequency 2f C at a sampling frequency 4f C to obtain two color difference signals each having a sampled frequency 4f C ; filtering said two color difference signals sampled at said sampling frequency 4f C for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively; sampling said two color difference signals after they have been filtered at a sampling frequency 4f SC to obtain two further sampled color difference signals; and encoding said two further sampled color difference signals using an oscillation signal having said frequency f SC to obtain said carrier chrominance signal.
Claim 12
Independent Claim
285 words
A method of reproducing a carrier chrominance signal with a carrier having a prescribed carrier frequency f SC from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency f C , comprising the steps of: sampling said low-range-converted chrominance signal at a sample frequency 4f C to obtain a sampled low-range-converted chrominance signal; inverting said sampled low-range-converted chrominance signal at cycles of 2f C to obtain an alternately inverting low-range-converted chrominance signal which alternately inverts at intervals of 1/(2f C ); sampling and holding said alternately inverting low-range-converted chrominance signals with a first clock signal having a frequency 2f C and a second clock signal having said frequency 2f C and a phase shifted by 180° from that of said first clock signal to obtain two color difference signals each having a sampled frequency 2f C ; sampling the sampled and held two color difference signals each having said sampled frequency 2f C at a sampling frequency 4f C to obtain two color difference signals each having a sampled frequency 4f C ; filtering said two color difference signals sampled at said sampling frequency 4f C for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively; sampling said two color difference signals after they have been filtered at a sampling frequency 4f SC to obtain two further sampled color difference signals; and encoding said two further sampled color difference signals using an oscillation signal having said frequency f SC to obtain said carrier chrominance signal.
Claim 13
Independent Claim
127 words
A method of reproducing two color difference signals from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency, comprising the steps of: demodulating said low-range-converted chrominance signal to obtain two color difference signals; and filtering said two color difference signals for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively; and sampling and holding said two color difference signals after they have been filtered at a predetermined sampling frequency to eliminate high frequency components having frequencies outside of a frequency range of said two color difference signals.
Claim 14
Independent Claim
127 words
A method of reproducing two color difference signals from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency, comprising the steps of: demodulating said low-range-converted chrominance signal to obtain two color difference signals; and filtering said two color difference signals for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively; and sampling and holding said two color difference signals after they have been filtered at a predetermined sampling frequency to eliminate high frequency components having frequencies outside of a frequency range of said two color difference signals.
Claim 15
Dependent Claim
76 words
A method according to claim 9, wherein said demodulating step comprises the steps of: multiplying said low-range-converted chrominance by a first oscillation signal having said low-range-converted carrier frequency to obtain one of said two color difference signals; and multiplying said low-range-converted chrominance signal by a second oscillation signal having said low-range-converted carrier frequency and a phase shifted by 90° from that of said first oscillation signal to obtain the other of said two color difference signals.
Claim 16
Independent Claim
174 words
A method of reproducing two color difference signals from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency f C , comprising the steps of: sampling said low-range-converted chrominance signal at a sampling frequency 4f C to obtain a sampled low-range-converted chrominance signal; inverting said sampled low-range-converted chrominance signal at cycles of 2f C to obtain an alternately inverting low-range-converted chrominance signal which alternately inverts at intervals of 1/(2f C ); sampling said alternately inverting low-range-converted chrominance signal with a first clock signal having a frequency 2f C and a second clock signal having said frequency 2f C and a phase shifted by 180° from that of said first clock signal to obtain two color difference signals; and filtering said two color difference signals for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively.
Claim 17
Independent Claim
174 words
A method of reproducing two color difference signals from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency f C , comprising the steps of: sampling said low-range-converted chrominance signal at a sampling frequency 4f C to obtain a sampled low-range-converted chrominance signal; inverting said sampled low-range-converted chrominance signal at cycles of 2f C to obtain an alternately inverting low-range-converted chrominance signal which alternately inverts at intervals of 1/(2f C ); sampling said alternately inverting low-range-converted chrominance signal with a first clock signal having a frequency 2f C and a second clock signal having said frequency 2f C and a phase shifted by 180° from that of said first clock signal to obtain two color difference signals; and filtering said two color difference signals for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively.
Claim 18
Dependent Claim
39 words
A method according to claim 11, further comprising a step, between said sampling step and said filtering step, of interpolating said two color difference signals to obtain two color difference signals each having a sampled frequency 4f C .
Claim 19
Independent Claim
227 words
A method of reproducing two color difference signals from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency f C , comprising the steps of: sampling said low-range-converted chrominance signal at a sampling frequency 4f C to obtain a sampled low-range-converted chrominance signal; inverting said sampled low-range-converted chrominance signal at cycles of 2f C to obtain an alternately inverting low-range-converted chrominance signal which alternately inverts at intervals of 1/(2f C ); sampling and holding said alternately inverting low-range-converted chrominance signal with a first clock signal having a frequency 2f C and a second clock signal having said frequency 2f C and a phase shifted by 180° from that of said first clock signal to obtain two color difference signals each having a sampled frequency 2f C ; sampling the sampled and held two color difference signals each having said sampled frequency 2f C at a sampling frequency 4f C to obtain two color difference signals each having a sampled frequency 4f C ; and filtering said two color difference signals sampled at said sampling frequency 4f C for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively.
Claim 20
Independent Claim
227 words
A method of reproducing two color difference signals from a low-range-converted chrominance signal with a carrier having a low-range-converted carrier frequency f C , comprising the steps of: sampling said low-range-converted chrominance signal at a sampling frequency 4f C to obtain a sampled low-range-converted chrominance signal; inverting said sampled low-range-converted chrominance signal at cycles of 2f C to obtain an alternately inverting low-range-converted chrominance signal which alternately inverts at intervals of 1/(2f C ); sampling and holding said alternately inverting low-range-converted chrominance signal with a first clock signal having a frequency 2f C and a second clock signal having said frequency 2f C and a phase shifted by 180° from that of said first clock signal to obtain two color difference signals each having a sampled frequency 2f C ; sampling the sampled and held two color difference signals each having said sampled frequency 2f C at a sampling frequency 4f C to obtain two color difference signals each having a sampled frequency 4f C ; and filtering said two color difference signals sampled at said sampling frequency 4f C for eliminating even order harmonic components of said two color difference signals and noise components, said filtering step comprising the steps of: delaying said two color difference signals by a predetermined time; and adding said two color difference signals and the delayed two color difference signals, respectively.
References Cited (Backward Citations)
US3872498A
Cited
US3872497A
Cited
US3968514A
Cited
US4326216A
Cited
US3938179A
Cited
US4051517A
Cited
US3969757A
Cited
US4110761A
Cited
US3996610A
Cited
US4200881A
Cited
US4145705A
Cited
US4204220A
Cited
US4400742A
Cited
US4220964A
Cited
US4258384A
Cited
US4374396A
Cited
US4396953A
Cited
US4584613A
Cited
US4549225A
Cited
US4496992A
Cited
US4531149A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-28 | 1991-12-28 | 1992-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-28 | 1995-12-28 | 1996-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-28 | 1999-12-28 | 2000-06-28 | $7700.00 | Window Closed / Lapsed |