US4169988A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Raster distortion correction circuit
Assignee: RCA Licensing Corp
•
Filing: 1978-04-20
•
Granted: 1979-10-02
•
Expires: 1998-04-20
Abstract
Abstract A side pincushion correction circuit is coupled to a horizontal resonant retrace circuit which includes a retrace capacitor and a horizontal deflection winding. The correction circuit includes an inductance and a controllable switch which is turned on during each horizontal retrace interval. A compensating circuit comprising secondary winding of a flyback transformer is coupled to the inductance and reflects the inductance onto the primary winding side in series with the deflection winding when the switch is open circuited and reflects the inductance in parallel with the deflection winding when the switch is conducting. The on-off ratio of the switch during horizontal retrace is modulated at a vertical parabolic rate to achieve side pincushion correction. The turns ratio of the flyback transformer is selected to adjust the resonant frequency and the retrace time modulation created by the correction circuit.
Inventors
- 👤 Hans-Rudolf Fecht
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:28
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/16; H04N3/22; H04N3/23; H04N3/233
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
191 words
A raster distortion correction circuit, comprising: a deflection winding; a deflection circuit coupled to said deflection winding for establishing first and second intervals within a deflection cycle; a capacitance coupled to said deflection winding for forming a resonant circuit during said first interval; an inductance coupled to said resonant circuit; a controllable switch coupled to said inductance; control means coupled to said controllable switch for providing control signals to said switch for changing the conductive states of said switch, said control means varying the duration of said first conductive state relative to said second conductive state within said first interval in a manner correcting for raster distortion; and compensating means for coupling said inductance during said first interval in series with said deflection winding when said switch is in one of said first and second conductive states and for coupling said inductance during said first interval in parallel with said deflection winding when said switch is in the other of said first and second conductive states for adjusting the resonant frequency of said resonant circuit during said first interval for adjusting the duration of said first interval to a desired amount.
Claim 2
Dependent Claim
191 words
A raster distortion correction circuit, comprising: a deflection winding; a deflection circuit coupled to said deflection winding for establishing first and second intervals within a deflection cycle; a capacitance coupled to said deflection winding for forming a resonant circuit during said first interval; an inductance coupled to said resonant circuit; a controllable switch coupled to said inductance; control means coupled to said controllable switch for providing control signals to said switch for changing the conductive states of said switch, said control means varying the duration of said first conductive state relative to said second conductive state within said first interval in a manner correcting for raster distortion; and compensating means for coupling said inductance during said first interval in series with said deflection winding when said switch is in one of said first and second conductive states and for coupling said inductance during said first interval in parallel with said deflection winding when said switch is in the other of said first and second conductive states for adjusting the resonant frequency of said resonant circuit during said first interval for adjusting the duration of said first interval to a desired amount.
Claim 3
Dependent Claim
41 words
A circuit according to claim 1, wherein said control signals vary at a vertical rate for varying the duration of said first conductive state relative to said second conductive state at a vertical parabolic rate for providing side pincushion distortion correction.
Claim 4
Dependent Claim
52 words
A circuit according to claim 2, wherein said compensating means comprises a transformer with a first winding coupled to said resonant circuit and with a said second winding coupled to said inductance, the turns ratio of said first winding to said second winding selected to adjust said duration to said desired amount.
Claim 5
Dependent Claim
38 words
A circuit according to claim 3, wherein said turns ratio approximately equals L H L m , where L H equals the inductance value of said deflection winding and L m equals the inductance value of said inductance.
Claim 6
Dependent Claim
13 words
A circuit according to claim 2, wherein said controllable switch is bidirectionally conductive.
Claim 7
Dependent Claim
36 words
A circuit according to claim 5 including a second capacitance coupled to said controllable switch for forming a second resonant circuit with said inductance when said switch is conductive for providing an "S" shaping correction voltage.
Claim 8
Dependent Claim
42 words
A circuit according to claim 6, wherein varying the duration of said first conductive state relative to said second conductive state at a vertical parabolic rate modulates said "S" shaping correction voltage at a vertical rate for providing inside pincushion distortion correction.
Claim 9
Dependent Claim
52 words
A circuit according to claim 7, wherein said compensating means comprises a transformer with a first winding coupled to said resonant circuit and with a said second winding coupled to said inductance, the turns ratio of said first winding to said second winding selected to adjust said duration to said desired amount.
References Cited (Backward Citations)
US3906305A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-10-01 | 1983-04-02 | 1983-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-01 | 1987-04-02 | 1987-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-01 | 1991-04-02 | 1991-10-02 | $7700.00 | Window Closed / Lapsed |