Patent CA537144A successfully refreshed from Google Patents.
US3585285A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Subcarrier regeneration system
Assignee: Zenith Electronics LLC
•
Filing: 1968-11-21
•
Granted: 1971-06-15
•
Expires: 1988-11-21
Abstract
Abstract A subcarrier regeneration stage and control arrangement for a color television receiver includes a 3.58 MHz. crystal-controlled oscillator, a phase detector and a novel voltage-controllable phase shift network in the feedback loop of the oscillator for maintaining the oscillator in phase synchronism with a received NTSC reference burst signal. The phase shift network comprises a pair of transistors differentially gain-controlled by the phase detector output voltage and having their collectors coupled to respective ends of a passive phase shift circuit such that the output from one transistor is phase-advanced and the output from the other transistor is phase-retarded. The oscillator signal is concurrently applied to the emitters of the two transistors and translated through the network with a net phase shift dependent on the detector controlled gain differential between the two transistors. Also incorporated in the regeneration stage is a hue control circuit employing a second pair of transistors differentially gain-controlled by a DC control voltage from a viewer-adjustable hue control to vary the phase of the oscillator signal as applied to the demodulator. This second pair of transistors is forward biased by a control circuit during the intervals between synchronizing bursts to disable the phase detector, thereby minimizing drift and preventing the detector from responding to chrominance information signals and noise, and is back-biased during reference burst intervals to prevent translation of the oscillator output signal to the demodulator during these periods. Because the regeneration stage utilizes differentially paired transistors throughout and a minimum of inductive components, it is particularly well suited for construction in microelectronic form.
Inventors
- 👤 John L Rennick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:22
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/44; H04N9/455; H03; H03B; H03B5/00; H03B5/30; H03B5/32; H03B5/36; H03B2200/00; H03B2200/006; H03B2200/0098
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
140 words
A signal translating network providing an adjustable degree of phase shift to an applied input signal comprising: a first differential amplifier comprising a pair of amplifying devices each having input output, and common electrodes and at least one of said devicEs being gain dependent on an applied control voltage; phase shifting means coupled between the output electrodes of said amplifying devices; means for applying said input signal concurrently to the input electrodes of said amplifying devices; means for deriving from the output electrodes of said amplifying devices an output signal having a phase related to the phase of said input signal according to the differential in gain between said devices; and control means for applying said control voltage to said one device to adjust the relative gain of said amplifying devices and thereby determine the phase of said output signal.
Claim 2
Dependent Claim
140 words
A signal translating network providing an adjustable degree of phase shift to an applied input signal comprising: a first differential amplifier comprising a pair of amplifying devices each having input output, and common electrodes and at least one of said devicEs being gain dependent on an applied control voltage; phase shifting means coupled between the output electrodes of said amplifying devices; means for applying said input signal concurrently to the input electrodes of said amplifying devices; means for deriving from the output electrodes of said amplifying devices an output signal having a phase related to the phase of said input signal according to the differential in gain between said devices; and control means for applying said control voltage to said one device to adjust the relative gain of said amplifying devices and thereby determine the phase of said output signal.
Claim 3
Dependent Claim
31 words
A signal translating network as described in claim 1 wherein said amplifying devices are transistors, said input electrodes are emitters, said common electrodes are bases, and said output electrodes are collectors.
Claim 4
Dependent Claim
47 words
A signal translating network as described in claim 2 wherein said phase-shifting means comprises a network including a pair of series-connected capacitors coupled between the collectors of said amplifying devices and a resistor coupled between the juncture of said capacitors and a plane of fixed reference potential.
Claim 5
Dependent Claim
19 words
A signal translating network as described in claim 1 wherein said phase shifting means comprises a high pass filter.
Claim 6
Dependent Claim
41 words
A signal translating network as described in claim 1 wherein said input electrodes of said first and second amplifying devices are coupled together and said means for applying said input signal to said input electrodes comprises a constant current signal source.
Claim 7
Dependent Claim
25 words
A signal translating network as described in claim 1 wherein said control means applies a voltage to the common electrode of said one amplifying device.
Claim 8
Dependent Claim
38 words
A signal translating network as described in claim 1 wherein said control means comprises a differential voltage source connected to the common electrode of respective ones of said amplifying devices for differentially varying the gain of said devices.
Claim 9
Dependent Claim
81 words
A signal translating network as described in claim 7 in which said differential voltage source comprises a pair of active electron devices having input circuits for receiving a pair of signals to be compared and having output circuits which develop voltage levels which vary differentially in accordance with the relationship of said signal pair compared to a predetermined relationship, and in which said output circuits connect to said common electrodes of said amplifying devices, respectively, to control the gain thereof differentially.
Claim 10
Dependent Claim
83 words
A variable frequency oscillator including a signal translating network as described in claim 1 and further including another amplifier having input and output electrodes interconnected by a positive feedback means, comprising a frequency-determining means that is resonant at a predetermined frequency and further comprising said network, for applying a portion of said output signal derived from said network to said input electrode of said other amplifier to sustain oscillations at a frequency and phase conjointly determined by said frequency-determining means and said network.
Claim 11
Dependent Claim
51 words
A variable frequency oscillator as described in claim 9 in which said control means develops a control voltage which varies with phase deviations of said oscillator from a reference phase condition, and in which said control voltage is applied to said amplifier in a sense to maintain said reference phase condition.
Claim 12
Dependent Claim
28 words
A variable frequency oscillator as described in claim 9 wherein said frequency-determining means comprises a crystal which is resonant at approximately the mean operating frequency of said oscillator.
Claim 13
Dependent Claim
102 words
A variable frequency oscillator as described in claim 9 in which said other amplifier comprises a second pair of amplifying devices each having input, output, and common electrodes, in which the output electrode of one amplifying device of said other amplifier couples to said input electrodes of said amplifying devices of said network, in which the input electrode of the remaining amplifying device of said other amplifier couples to said output electrodes of said amplifying devices of said network, and in which said common electrodes of said amplifying devices of said other amplifier are coupled together to constitute a second differential amplifier.
Claim 14
Dependent Claim
76 words
A variable frequency oscillator as described in claim 12 which further includes a pair of emitter followers individually having emitter electrodes connected respectively to the input electrodes of said amplifying devices of said other amplifier, having base electrodes connected to a source of potential, with one of said base electrodes also coupled to one of said output electrodes of said amplifying devices of said network, and having collector electrodes connected to a source of bias potential.
Claim 15
Dependent Claim
161 words
A hue control for a color television receiver for applying a reference signal to a chrominance demodulator with an adjustably fixed phase comprising: a differential amplifier formed of a pair of reference signal amplifying devices each having input, output and common electrodes and at least one of said devices being gain dependent on an applied control voltage; phase shifting means coupled between the output electrodes of said devices; means for applying said reference signal concurrently to the input electrodes of said amplifying devices; means for deriving from the output electrodes of said devices and for applying to said demodulator an output signal having a phase related to the phase of said reference signal according to the differential in gain between said amplifying devices; and means comprising an adjustable voltage source for applying a control voltage of adjustable amplitude to said one amplifying device to adjust the relative gain of said amplifying devices and thereby vary the phase of said output signal.
Claim 16
Dependent Claim
161 words
A hue control for a color television receiver for applying a reference signal to a chrominance demodulator with an adjustably fixed phase comprising: a differential amplifier formed of a pair of reference signal amplifying devices each having input, output and common electrodes and at least one of said devices being gain dependent on an applied control voltage; phase shifting means coupled between the output electrodes of said devices; means for applying said reference signal concurrently to the input electrodes of said amplifying devices; means for deriving from the output electrodes of said devices and for applying to said demodulator an output signal having a phase related to the phase of said reference signal according to the differential in gain between said amplifying devices; and means comprising an adjustable voltage source for applying a control voltage of adjustable amplitude to said one amplifying device to adjust the relative gain of said amplifying devices and thereby vary the phase of said output signal.
Claim 17
Dependent Claim
121 words
A hue control as described in claim 14 for a receiver for utilizing a chrominance signal having recurrent reference sync bursts in addition to chroma information, which includes an active gating electron means coupled to said amplifying devices of said reference-signal differential amplifier and responsive to an applied gating pulse to be activated from a first operating condition, in which said gating device permits said differential amplifier to apply said reference signal to said demodulator, to a second operating condition, in which said gating device biases said amplifying devices of said reference-signal differential amplifier to a nonconductive state, and which further includes means for applying to said gating device an actuating pulse occuring in time coincidence with said recurrent sync bursts.
Claim 18
Dependent Claim
87 words
A hue control as described in claim 15 in which said amplifying devices of said reference-signal differential amplifier are normally biased to a conductive state by a bias network including a source and a series-connected impedance, and in which said gating means comprises a single normally nonconductive transistor having an output circuit coupled across said impedance and having an input circuit for receiving said actuating pulse to render said transistor conductive and modify the bias condition of said amplifying devices to render said reference-signal differential amplifier nonconductive.
Claim 19
Dependent Claim
172 words
A chrominance demodulation system for developing from a phase and amplitude modulate subcarrier and periodically recurrent reference sync burst signals a plurality of color information signals for application to the image reproducer of a color television receiver, which system comprises; a phase-controllable oscillator for producing a reference signal phase synchronized to said sync burst signal; demodulator means for utilizing said reference signal to derive said color information signals from said modulated subcarrier; a detector responsive to said reference signal and to said sync burst signal for generating a control signal having An amplitude which varies with variations in a predetermined characteristic of said reference signal or said sync burst signal; means for utilizing said control signal to adjust an operating parameter of said system that controls said predetermined signal characteristic; and means coupled between said oscillator and said demodulator means for translating said reference signal to said demodulator means only during the intervals between said sync burst signals and for rendering said detector responsive only during the presence of said burst signals.
Claim 20
Dependent Claim
172 words
A chrominance demodulation system for developing from a phase and amplitude modulate subcarrier and periodically recurrent reference sync burst signals a plurality of color information signals for application to the image reproducer of a color television receiver, which system comprises; a phase-controllable oscillator for producing a reference signal phase synchronized to said sync burst signal; demodulator means for utilizing said reference signal to derive said color information signals from said modulated subcarrier; a detector responsive to said reference signal and to said sync burst signal for generating a control signal having An amplitude which varies with variations in a predetermined characteristic of said reference signal or said sync burst signal; means for utilizing said control signal to adjust an operating parameter of said system that controls said predetermined signal characteristic; and means coupled between said oscillator and said demodulator means for translating said reference signal to said demodulator means only during the intervals between said sync burst signals and for rendering said detector responsive only during the presence of said burst signals.
Claim 21
Dependent Claim
71 words
A system as described in claim 17 in which said detector receives said reference signal and said sync burst in phase quadrature and derives therefrom a control signal indicative of the sense and extent in which the phase of said reference signal deviates from a predetermined phase condition, and in which said means for utilizing said control signal adjusts said oscillator to maintain said reference signal in said predetermined phase condition.
Claim 22
Dependent Claim
87 words
A system in accordance with claim 18 which includes another detector, means for applying said reference signal and sync burst to said other detector in an in-phase relation to develop a second control signal indicative of amplitude variations of said sync burst, and means for utilizing said second control signal to maintain said sync burst at a substantially constant amplitude, and in which said means for translating said reference signal renders said other detector responsive only in time coincidence with the response intervals of said quadrature-phase detector.
Claim 23
Dependent Claim
36 words
A chrominance demodulation system as described in claim 17 wherein said translating means includes a hue control arrangement for providing an adjustable amount of phase shift to said reference signal as translated to said demodulator means.
Claim 24
Dependent Claim
149 words
A chrominance demodulation system as described in claim 20 wherein said hue control arrangement comprises: a differential amplifier formed of first and second reference-signal amplifying devices each having input, output and common electrodes and at least one being gain dependent on an applied control voltage; phase-shifting means coupled between the output electrodes of said reference-signal amplifying devices; means for applying said reference signal concurrently to the input electrodes of said reference-signal amplifying devices; means coupled to said output electrodes of said reference-signal amplifying devices for applying said reference signal to said demodulator means with a phase related to the differential gain of said reference-signal amplifying devices; and means comprising an adjustable voltage source for applying a control voltage of adjustable amplitude to said one reference-signal amplifying device to vary the relative gain of said reference-signal amplifying devices and hence the hue of the image produced by said image reproducer.
Claim 25
Dependent Claim
288 words
A chrominance demodulation system for developing from a phase and amplitude modulated subcarrier and periodically recurrent reference burst signals a plurality of color information signals for application to the image reproducer of a color television receiver, which system comprises: a phase controllable oscillator for generating a reference signal phase-synchronized to said sync burst signal; demodulator means for utilizing said subcarrier and reference signals to develop a plurality of color information signals; translating means comprising a reference-signal amplifier having input, output and common electrodes, with said input electrode coupled to said oscillator and said output electrode coupled to said demodulator means to apply said reference signal thereto, said reference-signal amplifier being normally conductive and establishing said input electrode at a potential of a given polarity and a predetermined minimum amplitude but being nonconductive in the presence of an applied gating signal to reduce the potential of said input electrode to a level Below said minimum amplitude; means for applying a gating signal, occurring in time coincidence with said sync burst signal, to said reference signal amplifier; a detector which is conditionally responsive to said reference signal and to said sync burst signal for generating a control signal having an amplitude varying with variations in a predetermined characteristic of said signals and which is subject to being rendered nonresponsive by the application of a control potential of said given polarity and minimum amplitude; means for utilizing said control signal to adjust an operating parameter of said system that controls said predetermined signal characteristic; and means, including a connection from said detector to said input electrode, for applying said reference signal to said detector and for conditioning said detector to respond thereto only during the occurrence of said sync burst signal.
Claim 26
Dependent Claim
288 words
A chrominance demodulation system for developing from a phase and amplitude modulated subcarrier and periodically recurrent reference burst signals a plurality of color information signals for application to the image reproducer of a color television receiver, which system comprises: a phase controllable oscillator for generating a reference signal phase-synchronized to said sync burst signal; demodulator means for utilizing said subcarrier and reference signals to develop a plurality of color information signals; translating means comprising a reference-signal amplifier having input, output and common electrodes, with said input electrode coupled to said oscillator and said output electrode coupled to said demodulator means to apply said reference signal thereto, said reference-signal amplifier being normally conductive and establishing said input electrode at a potential of a given polarity and a predetermined minimum amplitude but being nonconductive in the presence of an applied gating signal to reduce the potential of said input electrode to a level Below said minimum amplitude; means for applying a gating signal, occurring in time coincidence with said sync burst signal, to said reference signal amplifier; a detector which is conditionally responsive to said reference signal and to said sync burst signal for generating a control signal having an amplitude varying with variations in a predetermined characteristic of said signals and which is subject to being rendered nonresponsive by the application of a control potential of said given polarity and minimum amplitude; means for utilizing said control signal to adjust an operating parameter of said system that controls said predetermined signal characteristic; and means, including a connection from said detector to said input electrode, for applying said reference signal to said detector and for conditioning said detector to respond thereto only during the occurrence of said sync burst signal.
References Cited (Backward Citations)
US3459884A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-14 | 1974-12-14 | 1975-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-14 | 1978-12-14 | 1979-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-14 | 1982-12-14 | 1983-06-15 | $7700.00 | Window Closed / Lapsed |