US3715472A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Color emphasis circuit for tv receivers
Assignee: Teledyne Inc
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Filing: 1971-01-13
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Granted: 1973-02-06
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Expires: 1991-01-13
Abstract
Abstract A circuit for enhancing a particular color in a color television receiver. A portion of the color signal is demodulated along the desired color axis, rectified and modulated with a phase controlled reference signal of like frequency. The signal so processed is added to the original color signal for normal demodulation. In a preferred version the color signal is applied through a diode to the base of a transistor having a threshold between the peak voltage appearing at the base with no color signal present and the peak voltage appearing at the base in the presence of a color signal in phase with the reference signal. The output signal of the transistor is then added back to the color signal to provide the enhanced color signal.
Inventors
- 👤 J Mctaggart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:38
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/643
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
129 words
In a color television receiver, a circuit for emphasizing a particular color comprising: a diode having first and second terminals; means for applying a color signal to the first terminal of the diode for demodulation and rectification; means for receiving from the second terminal of the diode the demodulated rectified color signal; means for combining a reference signal of like frequency and desired phase with the demodulated rectified color signal; a transistor having a conduction threshold between the peak voltage of the referenced signal and the sum of the peak voltages of the reference signal and the demodulated rectified color signal; means for applying the combined reference and demodulated rectified color signals to the base of the transistor, and means for deriving a color enhancement signal from the transistor.
Claim 2
Dependent Claim
129 words
In a color television receiver, a circuit for emphasizing a particular color comprising: a diode having first and second terminals; means for applying a color signal to the first terminal of the diode for demodulation and rectification; means for receiving from the second terminal of the diode the demodulated rectified color signal; means for combining a reference signal of like frequency and desired phase with the demodulated rectified color signal; a transistor having a conduction threshold between the peak voltage of the referenced signal and the sum of the peak voltages of the reference signal and the demodulated rectified color signal; means for applying the combined reference and demodulated rectified color signals to the base of the transistor, and means for deriving a color enhancement signal from the transistor.
Claim 3
Dependent Claim
129 words
In a color television receiver, a circuit for emphasizing a particular color comprising: a diode having first and second terminals; means for applying a color signal to the first terminal of the diode for demodulation and rectification; means for receiving from the second terminal of the diode the demodulated rectified color signal; means for combining a reference signal of like frequency and desired phase with the demodulated rectified color signal; a transistor having a conduction threshold between the peak voltage of the referenced signal and the sum of the peak voltages of the reference signal and the demodulated rectified color signal; means for applying the combined reference and demodulated rectified color signals to the base of the transistor, and means for deriving a color enhancement signal from the transistor.
Claim 4
Dependent Claim
129 words
In a color television receiver, a circuit for emphasizing a particular color comprising: a diode having first and second terminals; means for applying a color signal to the first terminal of the diode for demodulation and rectification; means for receiving from the second terminal of the diode the demodulated rectified color signal; means for combining a reference signal of like frequency and desired phase with the demodulated rectified color signal; a transistor having a conduction threshold between the peak voltage of the referenced signal and the sum of the peak voltages of the reference signal and the demodulated rectified color signal; means for applying the combined reference and demodulated rectified color signals to the base of the transistor, and means for deriving a color enhancement signal from the transistor.
Claim 5
Dependent Claim
39 words
A circuit as in claim 1 wherein the forward voltage drop across the diode is balanced against the forward voltage drop across the base emitter junction of the transistor to provide automatic temperature compensation to the transistor threshold bias.
Claim 6
Dependent Claim
25 words
A circuit as in claim 1 and further comprising means for varying the phase relation between the demodulated rectified color signal and the reference signal.
Claim 7
Dependent Claim
48 words
A circuit as in claim 3 and further comprising means for adding signals, means for applying to the signal adding means the color signal and the color enhancement signal, and means for deriving from the signal adding means a signal corresponding to the sum of the signals applied.
References Cited (Backward Citations)
US3525802A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-06 | 1976-08-07 | 1977-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-06 | 1980-08-07 | 1981-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-06 | 1984-08-07 | 1985-02-06 | $7700.00 | Window Closed / Lapsed |