Patent US3004705A successfully refreshed from Google Patents.
US3755805A
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US
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Character generator for producing characters on the screen of a cathode-ray tube
Assignee: US Philips Corp
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Filing: 1971-03-03
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Granted: 1973-08-28
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Expires: 1991-03-03
Abstract
Abstract Ultra-rapid character generator for use with a cathode-ray tube operating on straight line segments and equipped with a permanent store from which by means of a store word address a character codeword is passed to a transfer register, which transfers the relevant character codeword sequentially in a number of relevant groups of 5 bits to a decoder, 3 bits determining 8 line segment directions, 1 bit determining a single or double line segment length and 1 bit determining the display or non-display.
Inventors
- 👤 P Dandrel
- 👤 J Moreau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:49
CPC Classifications
G; G09; G09G; G09G1/00; G09G1/06; G09G1/08; G09G1/10; H; H03; H03M; H03M7/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
184 words
A character generator for producing characters on the screen of a cathode-ray tube, said characters being formed by straight line segments, the character generator comprising a permanent memory store with the segment information in a codeword of groups of bits, one group per segment, a pulse generator for producing phase-shifted pulses having a gating function, whereby pulses of the segment information are supplied sequentially, group after group, on the one hand through a transfer register to a digitalanalogue converter for providing deflection signals for the cathode-ray tube, and on the other hand to said cathode ray tube for the display or non-display of the segment, the character generator further comprising a decoder for decoding the segment information given for each character in its own codeword with groups of five bits, three bits determining one of eight line segment dIrections, one bit determining a single or double line segment length and one bit determining the display or non-display of the line segment on the screen of the cathode-ray tube, said decoder being connected between the transfer register and the digital-analogue converter and the cathode-ray tube.
Claim 2
Dependent Claim
184 words
A character generator for producing characters on the screen of a cathode-ray tube, said characters being formed by straight line segments, the character generator comprising a permanent memory store with the segment information in a codeword of groups of bits, one group per segment, a pulse generator for producing phase-shifted pulses having a gating function, whereby pulses of the segment information are supplied sequentially, group after group, on the one hand through a transfer register to a digitalanalogue converter for providing deflection signals for the cathode-ray tube, and on the other hand to said cathode ray tube for the display or non-display of the segment, the character generator further comprising a decoder for decoding the segment information given for each character in its own codeword with groups of five bits, three bits determining one of eight line segment dIrections, one bit determining a single or double line segment length and one bit determining the display or non-display of the line segment on the screen of the cathode-ray tube, said decoder being connected between the transfer register and the digital-analogue converter and the cathode-ray tube.
Claim 3
Dependent Claim
75 words
A character generator as claimed in claim 1 wherein the permanent memory store is of the type in which each character has its own word address, and wherein outputs carrying the character information in one codeword are fed to the transfer register, said transfer register being connected to said pulse generator providing the phase-shifted gate pulses, the character generator being synchronized with a clock pulse generator connected to the pulse generator and to the decoder.
Claim 4
Dependent Claim
84 words
A character generator as claimed in claim 1 wherein each of the code-words of the characters supplied by the store have a group of bits for the first segment comprising four bits and all further groups comprise five bits each, two of the bits in the first group of four bits determine the direction of the segment, the transfer register itself supplying beyond the store, by means of a biased terminal, the failing bit which is the same for each codeword, to the decoder.
Claim 5
Dependent Claim
50 words
A character generator as claimed in claim 2 wherein between the clock pulse generator and the pulse generator providing the phase-shifted gate pulses for the transfer register, a gate circuit is provided which operates as a character magnifying member in accordance with the passage or nonpassage of consecutive clock pulses.
Claim 6
Dependent Claim
42 words
A character generator as claimed in claim 2 wherein the clock pulse generator supplies pulses through two lines to the decoder, pulses having a duration t1 in one line thereof and pulses having a duration t2 2t1 in the other line thereof.
Claim 7
Dependent Claim
92 words
A character generator as claimed in claim 5 characterized in that the decoder comprises multi-input gates coupled with the transfer register and connected to each other, the outputs of the decoder being formed by outputs of gates of which one input of each gate is connected to one input on further gates for synchronization purposes, said inputs being coupled with outputs of further gates, to inputs of which are applied the fourth bits information of the transfer register and the pulses of the durations t1 and t2 of the clock pulse generator.
Claim 8
Dependent Claim
39 words
A character generator as claimed in claim 1, wherein the decoder comprises a gate of five inputs, to which five information outputs of the transfer register are connected, said gate supplying a character-end signal in the case of 0-information.
Claim 9
Dependent Claim
63 words
A character generator as claimed in claim 7 when using a store having character information in the form of a store codeword having an n number of groups presenting a maximum permissible total number of bits, the transfer register is provided with a group of inputs connected to a biassed terminal supplying the 0-information beyond the store for the (n + 1)th group.
Claim 10
Dependent Claim
37 words
A character generator as claimed in claim 8 wherein the store is of the type having a maximum length codeword of 64 bits, whilst the transfer register supplies 14 groups of 5 bits at its 5 outputs.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |