Dc regulating blanking insertion circuit and color matrix circuit

Claim 2

In a television receiver, a DC level regulating and blanking insertion circuit comprising: a. signal demodulating means for demodulating a modulated signal applied thereto, said signal demodulating means having a modulated signal input, a reference signal input, and a demodulated signal output, and also having a supply voltage input for receipt of a supply voltage, said signal demodulating means including means DC coupling said supply voltage input and said signal output, so that the DC level at said signal output is dependent on the DC level of said supply voltage, and so that blanking pulses in said supply voltage will produce corresponding blanking pulses at said signal output of amplitude dependent on the amplitude of the pulses in said supply voltage, b. means for providing a regulated DC supply voltage, c. control means having voltage control input means for receiving a control signal, said control means being connected in series between said means (b) and said supply voltage input for controlling the magnitude of said supply voltage dependent upon the magnitude of said control signal, d. means connected to said control input means for applying blanking pulses of predetermined amplitude thereto, for producing corresponding blanking pulses of predetermined amplitude at said supply voltage input, thus to produce corresponding blanking pulses of predetermined amplitude at said signal output, e. and means connected between said signal output and said control input means for detecting the DC level at the tips of said blanking pulses at said signal output and for applying a continuous error signal to said control input means to control the magnitude of said regulated DC supply voltage applied to said supply voltage input to maintain the DC level at the tips of said blanking pulses at said signal output at a substantially predetermined value, thereby maintaining the quiescent DC level at said signal output at a substantially fixed value between said blanking pulses.

Claim 3

Apparatus according to claim 1 wherein said means (e) includes diode means connected to said signal output, means biasing said diode for conduction only during said blanking pulses, means connected to said diode means for establishing a first DC voltage proportional to the DC voltage level at the tips of said blanking pulses at said signal output, and amplifying means controlled by said first voltage, said amplifying means being connected to said control input means to apply said continuous error signal thereto.

Claim 4

means for supplying blanking pulses to said second transistor,

Claim 5

means for supplying blanking pulses to said second transistor,

Claim 6

means connecting said second transistor to be normally non-conducting and to saturate when it receives said pulses, said last mentioned means including a resistor-divider network connected in series with said second transistOr between said means (b) and ground,

Claim 7

means connecting said second transistor to be normally non-conducting and to saturate when it receives said pulses, said last mentioned means including a resistor-divider network connected in series with said second transistOr between said means (b) and ground,

Claim 8

Apparatus according to claim 2 wherein said control means comprises a regulator transistor connected in series between said means (b) and said supply voltage input, said control input means being constituted by a control terminal of said regulator transistor.

Claim 9

Apparatus according to claim 3 wherein said means for applying blanking pulses of predetermined amplitude to said control terminal comprises:

Claim 10

and means connecting said resistor-divider network to said control terminal.

Claim 11

and means connecting said resistor-divider network to said control terminal.

Claim 12

Apparatus according to claim 1 wherein said television receiver is a color receiver, said signal demodulating means being a color demodulator, said modulated signal input being adapted to receive color signal information, said demodulator having three color outputs, each for a color difference signal, said demodulator including means for maintaining the DC voltage level at each output substantially the same as the DC voltage level at each other output, said signal output being one of said color outputs, said blanking pulses being horizontal and vertical blanking pulses.

Claim 13

Apparatus according to claim 5 wherein said color television receiver includes a picture tube having three electron guns, one for each of three colors; said apparatus further including three drive amplifiers, one connected to each of said color outputs, each drive amplifier having an output connected to one of said electron guns, each drive amplifier also having a DC level input; first, second, and third tracking resistors one connected to each of said DC level inputs and each connected to a common terminal, means for supplying a black and white video signal, said common terminal being connected to said means for supplying said black and white signal so that said tracking resistors control the DC level of said black and white signal at said DC level inputs, at least two of said tracking resistors being adjustable; said drive amplifiers being powered by a fixed DC voltage so that during unblanked intervals and in the absence of any potential applied to said common terminal by said means for supplying said black and white signal, the DC level at said DC level inputs is a predetermined value; and means for establishing a DC reference voltage at said common terminal equal to said predetermined value, thus to render said tracking resistors ineffective, so that said electron guns can be adjusted to coincident cutoff with said tracking resistors ineffective, and said reference voltage can then be removed and said tracking resistors adjusted for grey tracking of said electron guns.

Claim 14

Apparatus according to claim 6 wherein each drive amplifier includes a transistor having its base DC connected to one of said color outputs and having its emitter connected through a first bias resistor to a said tracking resistor, and a second bias resistor connected between ground and the junction of said first bias resistor and such tracking resistor.

Claim 15

Apparatus according to claim 6 wherein said television set further includes a variable brightness control resistor, and means connecting said brightness control resistor to set the DC level at said common terminal of said tracking resistors; and said means for establishing said reference voltage includes a reference resistor and a service switch, said service switch including contact means for disconnecting said brightness control resistor and for substituting said reference resistor, said television set also including vertical scanning circuits, said service switch further including contact means for disabling said vertical scanning circuits and for removing video signal information from said signal input of said signal processing means.

Claim 16

Apparatus according to claim 6 including variable grid resistors biasing said grids, so that adjustment for coincident cutoff may be made by adjusting said variable grid resistors.

Claim 17

In a television receiver, a DC level regulating and blanking insertion circuit comprising: a. signal demodulating means for demodulating a modulated signal applied thereto, said signal demodulating means having a modulated signal input, a reference signal input, and a demodulated signal output, and also having a supply voltage input for receipt of a supply voltage, said signal demodulating means including means DC coupling said supply voltage input and said signal output, so that the DC level at said signal output is dependent on the DC level of said supply voltage, b. said signal demodulating means including blanking pulse input means for receiving blanking pulses, and means coupled to said blanking pulse input means for producing corresponding blanking pulses at said signal output of amplitude dependent on the amplitude of the received blanking pulses, c. means for providing a regulated DC supply voltage, d. control means having voltage control input means for receiving a control signal, said control means being connected in series between said means (c) and said supply voltage input for controlling the magnitude of said supply voltage dependent upon the magnitude of said control signal, e. means connected to said pulse input means for applying blanking pulses of predetermined amplitude thereto, whereby to produce corresponding blanking pulses of predetermined amplitude at said signal output, f. and means connected between said signal output and said control input means for detecting the DC level at the tips of said blanking pulses at said signal output and for applying a continuous error signal to said control input means to control the magnitude of said regulated DC supply voltage applied to said supply voltage input to maintain the DC level at the tips of said blanking pulses at said signal output at a substantially predetermined value, thereby maintaining the quiescent DC level at said signal output at a substantially fixed value between said blanking pulses.

Claim 18

In a television receiver, a DC level regulating and blanking insertion circuit comprising: a. signal demodulating means for demodulating a modulated signal applied thereto, said signal demodulating means having a modulated signal input, a reference signal input, and a demodulated signal output, and also having a supply voltage input for receipt of a supply voltage, said signal demodulating means including means DC coupling said supply voltage input and said signal output, so that the DC level at said signal output is dependent on the DC level of said supply voltage, b. said signal demodulating means including blanking pulse input means for receiving blanking pulses, and means coupled to said blanking pulse input means for producing corresponding blanking pulses at said signal output of amplitude dependent on the amplitude of the received blanking pulses, c. means for providing a regulated DC supply voltage, d. control means having voltage control input means for receiving a control signal, said control means being connected in series between said means (c) and said supply voltage input for controlling the magnitude of said supply voltage dependent upon the magnitude of said control signal, e. means connected to said pulse input means for applying blanking pulses of predetermined amplitude thereto, whereby to produce corresponding blanking pulses of predetermined amplitude at said signal output, f. and means connected between said signal output and said control input means for detecting the DC level at the tips of said blanking pulses at said signal output and for applying a continuous error signal to said control input means to control the magnitude of said regulated DC supply voltage applied to said supply voltage input to maintain the DC level at the tips of said blanking pulses at said signal output at a substantially predetermined value, thereby maintaining the quiescent DC level at said signal output at a substantially fixed value between said blanking pulses.

Claim 19

A color television receiver having vertical scan means; video signal receiving means, including means for providing a black and white video signal and means for providing color signal receiving means and adapted to receive color signal information therefrom, said demodulator having a plurality of color outputs, each for a color difference signal, means connected to said demodulator for regulating the DC levels at said outputs each at substantially the same predetermined level during unblanked intervals in the absence of said color signal information; said receiver further including a picture tube having a plurality of electron guns, each for a color; said receiver further including a plurality of drive amplifiers, one connected to each of said color outputs, each drive amplifier having an output connected to one of said electron guns, each drive amplifier also having a DC level input; first, second, and third tracking resistors one connected to each of said DC level inputs and each connected to a common terminal, said common terminal being coupled to said means for providing said black and white video signal, so that said tracking resistors control the DC level of said black and white signal at said DC level inputs, at least two of said tracking resistors being adjustable; first switching means operative for switching said vertical scan means and said video signal receiving means to collapse said vertical scan and to remove said color signal information from said demodulator and said black and white video signal from said common terminal; means for energizing said drive amplifiers with a fixed DC voltage so that during unblanked intervals and in the absence of any potential applied to said common terminal by said means for providing said black and white signal, the DC level at said DC level inputs is a predetermined value; second switch means operative for establishing a DC reference voltage at said common terminal equal to said predetermined value, thus to render said tracking resistors ineffective, so that when said first and second switch means are operated, said electron guns can be adjusted to coincident cutoff with said tracking resistors ineffective, and then with said first and second switch means unoperated and with only a black and white video signal supplied to said receiver, said tracking resistors can be adjusted for grey tracking of said electron guns.

Claim 20

A color television receiver having vertical scan means; video signal receiving means, including means for providing a black and white video signal and means for providing color signal receiving means and adapted to receive color signal information therefrom, said demodulator having a plurality of color outputs, each for a color difference signal, means connected to said demodulator for regulating the DC levels at said outputs each at substantially the same predetermined level during unblanked intervals in the absence of said color signal information; said receiver further including a picture tube having a plurality of electron guns, each for a color; said receiver further including a plurality of drive amplifiers, one connected to each of said color outputs, each drive amplifier having an output connected to one of said electron guns, each drive amplifier also having a DC level input; first, second, and third tracking resistors one connected to each of said DC level inputs and each connected to a common terminal, said common terminal being coupled to said means for providing said black and white video signal, so that said tracking resistors control the DC level of said black and white signal at said DC level inputs, at least two of said tracking resistors being adjustable; first switching means operative for switching said vertical scan means and said video signal receiving means to collapse said vertical scan and to remove said color signal information from said demodulator and said black and white video signal from said common terminal; means for energizing said drive amplifiers with a fixed DC voltage so that during unblanked intervals and in the absence of any potential applied to said common terminal by said means for providing said black and white signal, the DC level at said DC level inputs is a predetermined value; second switch means operative for establishing a DC reference voltage at said common terminal equal to said predetermined value, thus to render said tracking resistors ineffective, so that when said first and second switch means are operated, said electron guns can be adjusted to coincident cutoff with said tracking resistors ineffective, and then with said first and second switch means unoperated and with only a black and white video signal supplied to said receiver, said tracking resistors can be adjusted for grey tracking of said electron guns.