Cathode ray tube control apparatus for displaying upper and lower case characters using a single matrix

Claim 2

A cathode ray tube display system including a cathode ray tube, keyboard entry and storage means coupled to said tube, said keyboard entry and storage means including means for generating predetermined binary coded signals designating which character included in a set of characters is to be displayed along a horizontal line starting from a normal line position, said tube having major and minor vertical deflection generation means operative to generate major and minor positioning waveforms respectively for conditioning major and minor driver circuits for driving major and minor vertical coils in a vertical direction, said minor vertical deflection driver circuit means being operative to generate a high frequency pulse waveform for producing a predetermined number of character writing strokes for each of the characters to be written along said line, each of said strokes having a height corresponding to a number of spaces, said system further including improved positioning apparatus, coupled to said vertical deflection driver circuit means, said positioning apparatus comprising: decoder circuit means coupled to said keyboard entry and storage means, said decoding circuit means including logic circuit means for generating a control signal in response to any one of a predetermined number of characters comprising a special group of characters within said set which have a similar characteristic; and, amplifier circuit means including input means and output means, said input means being coupled to said logic circuit means and to said major vertical generation circuit means, and said output means being coupled to said vertical deflection driver circuit means, said amplifier circuit means being responsive to the joint application of said control signal and said positioning waveform to said input means to condition said amplifier circuit output means to apply an output signal to said deflection driver circuit means which produces an incremental vertical shift in said one of said predetermined number of characters from said normal line position.

Claim 3

Positioning apparatus for use in a cathode ray tube display system including data entry and storage means for generating coded signals representative of a different ones of the characters included in a set of characters to be displayed along a horizontal line starting from a normal line position, a cathode ray tube coupled to said entry and storage means, said tube having major and minor horizontal deflection and vertical deflection generation circuit means operative to generate major and minor positioning waveforms to condition major and minor deflection driver circuits respectively for driving a horizontal coil and major vertical coil and a minor vertical coil coupled to said tube for deflecting the electron beam along said horizontal line and in a vertical direction, said minor vertical deflection driver circuit means being operative to generate a high frequency pulse waveform for producing character writing strokes for the characters to be written along said line, each stroke having a height correspondinG to a number of spaces, said positioning apparatus comprising: decoder circuit means coupled to said data entry and storage means, said decoder circuit means being operative to generate a control signal upon decoding each one of a group of special characters included within said set; and, vertical deflection amplifier circuit means coupled to said major vertical deflection driver circuit means and to said decoder circuit means, said vertical deflection amplifier circuit means including: amplifier circuit means having at least one input terminal and an output terminal; and a plurality of input impedance means, each of said plurality of impedance means having an input and an output terminal, said output terminals of each of said input impedance means being connected in common to said input terminal of said amplifier circuit means, said input terminal of a predetermined first one of said plurality of impedance means being coupled to receive said major vertical positioning voltage waveform from said vertical deflection generation circuit means for driving said major vertical coil establishing said normal line position along which characters are to be written, said input terminal of a predetermined second one of said plurality of impedance means being coupled to receive said control signal, said amplifier circuit means being conditioned by the joint application of said major vertical positioning voltage waveform and said control signal to produce a first predetermined voltage level at said output terminal to condition said major vertical driver circuit means to change the deflection current in said vertical major coil by a first incremental amount during a character interval so as to shift vertically said each one of said group of special characters by an incremental amount from said normal line position so that each of said characters can be more easily read.

Claim 4

Positioning apparatus for use in a cathode ray tube display system including data entry and storage means for generating coded signals representative of a different ones of the characters included in a set of characters to be displayed along a horizontal line starting from a normal line position, a cathode ray tube coupled to said entry and storage means, said tube having major and minor horizontal deflection and vertical deflection generation circuit means operative to generate major and minor positioning waveforms to condition major and minor deflection driver circuits respectively for driving a horizontal coil and major vertical coil and a minor vertical coil coupled to said tube for deflecting the electron beam along said horizontal line and in a vertical direction, said minor vertical deflection driver circuit means being operative to generate a high frequency pulse waveform for producing character writing strokes for the characters to be written along said line, each stroke having a height correspondinG to a number of spaces, said positioning apparatus comprising: decoder circuit means coupled to said data entry and storage means, said decoder circuit means being operative to generate a control signal upon decoding each one of a group of special characters included within said set; and, vertical deflection amplifier circuit means coupled to said major vertical deflection driver circuit means and to said decoder circuit means, said vertical deflection amplifier circuit means including: amplifier circuit means having at least one input terminal and an output terminal; and a plurality of input impedance means, each of said plurality of impedance means having an input and an output terminal, said output terminals of each of said input impedance means being connected in common to said input terminal of said amplifier circuit means, said input terminal of a predetermined first one of said plurality of impedance means being coupled to receive said major vertical positioning voltage waveform from said vertical deflection generation circuit means for driving said major vertical coil establishing said normal line position along which characters are to be written, said input terminal of a predetermined second one of said plurality of impedance means being coupled to receive said control signal, said amplifier circuit means being conditioned by the joint application of said major vertical positioning voltage waveform and said control signal to produce a first predetermined voltage level at said output terminal to condition said major vertical driver circuit means to change the deflection current in said vertical major coil by a first incremental amount during a character interval so as to shift vertically said each one of said group of special characters by an incremental amount from said normal line position so that each of said characters can be more easily read.

Claim 5

The positioning apparatus of claim 2 wherein said decoding circuit means includes a plurality of first gating circuit means, each of said gating circuit means being connected to said data entry and storage means and arranged to decode a different one of said group of special characters and each of said gating circuit means including means for receiving a timing signal having a predetermined duration corresponding to said character interval, each of said plurality of gating circuits being operative to generate said control signal in response to receiving signals coded to represent a different one of said group of special characters from said data entry and storage means.

Claim 6

The positioning apparatus of claim 3 wherein said decoding circuit means further includes output logic circuit means coupled to each of said plurality of gating circuit means, each of said plurality of gating means upon decoding said different one of said group of special characters being operative to condition said output logic circuit means to generate said control signal having a predetermined voltage level.

Claim 7

The positioning apparatus of claim 4 wherein said output logic circuit means includes an amplifier circuit operative to produce said predetermined voltage level of said control signal so as to correspond to a voltage level representative of a binary ONE in said system.

Claim 8

The positioning apparatus of claim 3 wherein each of said plurality of gating circuit means include an AND gate and wherein each of said plurality of gating circuit means is connected to decode signals coded to represent a different one of said group of special characters corresponding to lower case characters g, j, p, q and y.

Claim 9

The positioning apparatus of claim 2 wherein said predetermined first and second ones of said impedance means selected to have first and second values of impedance respectively, said first and second values of impedance being selected to be a predetermined ratio so as to cause the voltage level applied to said input terminal of said amplifier circuit means to be decreased by a predeterminEd amount from the voltage produced by said major vertical positioning voltage waveform.

Claim 10

The positioning apparatus of claim 7 wherein said predetermined ratio corresponds to a 10 to 1 ratio.

Claim 11

The positioning apparatus of claim 7 wherein said first and second ones of said impedance means are resistances said ratio for said first and second resistances being selected to decrease said voltage level applied to said input terminal by a predetermined amount which corresponds to a shift in said character of two spaces out of said number of spaces.

Claim 12

The positioning apparatus of claim 7 wherein said major vertical positioning voltage waveform and control signals are of the same polarity.

Claim 13

The positioning apparatus of claim 2 wherein said decoder means further includes second gating means for generating a special symbol signal upon decoding at least one other type of special character and wherein said input terminal of a third one of said impedance means is connected to receive said special symbol signal, said vertical amplifier circuit means being conditioned by the joint application of said major vertical positioning voltage waveform and said special symbol signal to produce a second predetermined voltage level at said output terminal to condition said major vertical driver circuit means to change said deflection current by a second incremental amount different from said first incremental amount so as to shift vertically said other type of special character by a predetermined amount from said normal line position so as to position said other type of special character in a predetermined manner.

Claim 14

The positioning apparatus of claim 11 wherein said first, second and third ones of said impedance means are resistances and each having a predetermined value, said first and third values being selected to be of a predetermined ratio so as to cause the voltage level applied to said input terminal of said amplifier circuit means to increase by a predetermined amount from the voltage applied to said input terminal produced by said major vertical positioning voltage waveform.

Claim 15

The positioning apparatus of claim 11 wherein said major vertical positioning voltage waveform and said special symbol signal are of the opposite polarity.

Claim 16

The positioning apparatus of claim 11 wherein said gating means including means for receiving a timing signal having a predetermined duration corresponding to said character interval and inverter circuit means coupled to said gating means, said gating means being operative in response to receiving signals coded to represent said special character to condition said inverter circuit means to generate said special symbol signal.

Claim 17

The positioning apparatus of claim 2 wherein said vertical amplifier means further includes a differential amplifier circuit means having a non-inverting terminal and an inverting input terminal, said input terminal being connected to said non-inverting terminal of said amplifier means and said inverting input terminal being coupled to said major vertical deflection coil for receiving a feedback voltage and said differential amplifier circuit means being operative in response to signals applied to said non-inverting and inverting terminals to produce a difference voltage for application to said output terminal.

Claim 18

The positioning apparatus of claim 15 wherein said vertical amplifier further includes current amplifier circuit means having an input circuit and an output circuit, said input circuit being coupled to receive said difference voltage from said differential amplifier circuit means and said output circuit being coupled to said output terminal, said current amplifier circuit means being operative to connect said difference voltage into a current waveform for driving said deflection circuit means.

Claim 19

The positioning apparatus of claim 16 wherein said current amplifier circuit means and said deflection circuit means each include a pair of complementary typE transistors connected in an emitter follower configuration for producing said current waveform.

Claim 20

In a cathode ray tube display system including a cathode ray tube, keyboard input means, an encoder coupled to said keyboard input means, said encoder being operative in response to a key selection to produce output binary code signals representative of a character within a set of upper and lower case characters to be displayed on said tube along a horizontal line, storage register means coupled to receive said output binary code signals from said encoder means for coupling said cathode ray tube to said register storage means, said tube having major and minor horizontal deflection and vertical deflection generation circuit means operative to generate major and minor positioning waveforms to condition major and minor deflection driver circuit means respectively to drive major horizontal coil and major vertical coil and a minor vertical coil coupled to said tube for deflecting the electron beam along said horizontal line and in a vertical direction, said minor vertical deflection driver circuit means being operative to generate a high frequency pulse waveform for producing character writing strokes, a number of which define a character raster for each of the characters to be written along said line, each stroke having a height corresponding to a number of spaces, said display system further including positioning apparatus comprising: decoder circuit means coupled to said storage register, said decoder circuit means including means for generating a control signal upon sensing when said register storage means stores binary code signals which correspond to any one of a plurality of characters each of which can be written below said horizontal line and included within said set of characters; and, vertical deflection amplifier circuit means including input means and output means, said input means being coupled to receive said control signal and said major vertical positioning voltage waveform, said output means being coupled to said vertical deflection driver circuit means and said input means being responsive to the joint application of said control signal and said positioning voltage waveform to condition said amplifier circuit output means to apply an output signal to said deflection circuit means which produces an incremental vertical shift in the character raster for a character interval so that the character written during said character interval is displaced from said line enabling it to be more easily read.

Claim 21

In a cathode ray tube display system including a cathode ray tube, keyboard input means, an encoder coupled to said keyboard input means, said encoder being operative in response to a key selection to produce output binary code signals representative of a character within a set of upper and lower case characters to be displayed on said tube along a horizontal line, storage register means coupled to receive said output binary code signals from said encoder means for coupling said cathode ray tube to said register storage means, said tube having major and minor horizontal deflection and vertical deflection generation circuit means operative to generate major and minor positioning waveforms to condition major and minor deflection driver circuit means respectively to drive major horizontal coil and major vertical coil and a minor vertical coil coupled to said tube for deflecting the electron beam along said horizontal line and in a vertical direction, said minor vertical deflection driver circuit means being operative to generate a high frequency pulse waveform for producing character writing strokes, a number of which define a character raster for each of the characters to be written along said line, each stroke having a height corresponding to a number of spaces, said display system further including positioning apparatus comprising: decoder circuit means coupled to said storage register, said decoder circuit means including means for generating a control signal upon sensing when said register storage means stores binary code signals which correspond to any one of a plurality of characters each of which can be written below said horizontal line and included within said set of characters; and, vertical deflection amplifier circuit means including input means and output means, said input means being coupled to receive said control signal and said major vertical positioning voltage waveform, said output means being coupled to said vertical deflection driver circuit means and said input means being responsive to the joint application of said control signal and said positioning voltage waveform to condition said amplifier circuit output means to apply an output signal to said deflection circuit means which produces an incremental vertical shift in the character raster for a character interval so that the character written during said character interval is displaced from said line enabling it to be more easily read.