US4584600A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital filter for the chrominance channel of a color-television set
Assignee: ITT Inc
•
Filing: 1983-09-22
•
Granted: 1986-04-22
•
Expires: 2003-09-22
Abstract
Abstract A digital filter serves to compensate for the reduction in the amplitude of the chrominance-subcarrier reference (fc) caused by the passband of the intermediate frequency stages, and thus to achieve a flat response in the filter's passband within the chrominance-channel bandwidth. The transfer function of the digital filter is Y(z)/X(z)=T(z)=1/a+z.sup.-1 +z.sup.-2 /a, where a is a number presettable by the manufacturer of the color-television set but constant in operation.
Inventors
- 👤 Peotr Baker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:27
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/646; H04N5/00; H04N5/14; H04N5/21; H04N5/211; H04N5/44
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
126 words
A digital filter for use in a digital chrominance channel comprising: an input terminal; an output terminal; at least one adder; a multiplier having a multiplicand factor of 1/a wherein "a" is a presetable number of which is constant during operation of said digital filter; and a plurality of delay elements each providing a delay equal to one-fourth of the period of the chrominance-subcarrier reference frequency fc; wherein the frequency of the clock signal of the digital filter is four times the frequency fc; said at least one adder, said multiplier, and said plurality of delay elements being interconnected to provide a transfer function T(z) between said input and output terminal wherein T(z)=1/a+z -1 +z -2 /a where z is the variable of the z plane.
Claim 2
Dependent Claim
126 words
A digital filter for use in a digital chrominance channel comprising: an input terminal; an output terminal; at least one adder; a multiplier having a multiplicand factor of 1/a wherein "a" is a presetable number of which is constant during operation of said digital filter; and a plurality of delay elements each providing a delay equal to one-fourth of the period of the chrominance-subcarrier reference frequency fc; wherein the frequency of the clock signal of the digital filter is four times the frequency fc; said at least one adder, said multiplier, and said plurality of delay elements being interconnected to provide a transfer function T(z) between said input and output terminal wherein T(z)=1/a+z -1 +z -2 /a where z is the variable of the z plane.
Claim 3
Dependent Claim
121 words
A digital filter in accordance with claim 1 comprising a second adder; and wherein said input terminal is coupled to an input of a first one of said plurality of delay elements and to a first input of said one adder; said first delay element has an output coupled to said output terminal; a second one of said plurality of delay elements has an input coupled to said first delay element output and an output coupled to a second input of said one adder; and said multiplier has a first input coupled to the output of said one adder, a second input receiving a representation of the number "a", and an output coupled to the second input of said second adder.
Claim 4
Dependent Claim
10 words
A digital filter in accordance with claim 1 wherein -2≦a≦-10.
Claim 5
Dependent Claim
10 words
A digital filter in accordance with claim 2 wherein -2≦a≦-10.
Claim 6
Dependent Claim
29 words
A digital filter in accordance with claim 1 wherein each of said at least one adder, said multiplier and said plurality of delay elements process multidigit data in parallel.
Claim 7
Dependent Claim
29 words
A digital filter in accordance with claim 3 wherein each of said at least one adder, said multiplier and said plurality of delay elements process multidigit data in parallel.
Claim 8
Dependent Claim
31 words
A digital filter in accordance with claim 2 wherein each of said one adder, said second adder, said multiplier, and said first and second delay elements process multidigit data in parallel.
Claim 9
Dependent Claim
31 words
A digital filter in accordance with claim 4 wherein each of said one adder, said second adder, said multiplier, and said first and second delay elements process multidigit data in parallel.
Claim 10
Dependent Claim
126 words
A digital filter in accordance with claim 1 comprising a second adder and wherein: said multiplier has a first input coupled to said input terminal and a second input receiving a representation of the number "a", and an output coupled to the input of a first one of said delay elements; said at least one adder having a first input coupled to the output of said first delay element, a second input coupled to said input terminal and an output coupled to the input of a second one of said delay element; said second adder having a first input coupled to the output of said second delay element, a second input coupled to the output of said multiplier and an output coupled to said output terminal.
Claim 11
Dependent Claim
10 words
A digital filter in accordance with claim 9 wherein -2≦a≦-10.
Claim 12
Dependent Claim
29 words
A digital filter in accordance with claim 9 wherein each of said at least one adder, said multiplier and said plurality of delay elements process multidigit data in parallel.
Claim 13
Dependent Claim
29 words
A digital filter in accordance with claim 10 wherein each of said at least one adder, said multiplier and said plurality of delay elements process multidigit data in parallel.
References Cited (Backward Citations)
US4356558A
Cited
US4403245A
Cited
US4456893A
Cited
JPS58205379A
Cited
JPS5916490A
Cited
EP0105072A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-21 | 1989-10-21 | 1990-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-21 | 1993-10-21 | 1994-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-21 | 1997-10-21 | 1998-04-22 | $7700.00 | Window Closed / Lapsed |