Did You Know...
...Chester Carlson was a patent agent who tired of having to make multiple copies of patent applications using the only duplication method available at the time: carbon paper. In 1959 he came up with a new copying system and took it to IBM for evaluation. The "experts" at IBM determined potential sales to be only 5,000 units because people wouldn't want to use a bulky machine when they had carbon paper. Carlson's invention was the xerography process, the company founded on the system is Xerox.
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| Number | Title | Issue Date |
| 5436673 | Video signal color correction based on color hue Memories are provided for correction signal values respectively for a hue signal, a saturation signal and a luminance signal derived from a digital color television signal. Each of the memories consists of two memory units which are alternately used for s... | 07/25/1995 |
| 5365529 | Circuitry for detecting and correcting errors in data words occurring in Reed-Solomon coded blocks and determining when errors are uncorrectable by syndrome analysis, Euclid's algorithm and a Chien search Circuitry for detecting and correcting errors in data words occurring in Reed-Solomon coded blocks contains a plurality of stages. One stage constructs syndromes in the data flowing through the blocks. Another stage detects erasures in the syndromes. Anot... | 11/15/1994 |
| 5355225 | Video signal color correction with dual function memories and color window Memories are provided for correction signal values respectively for a hue signal, a saturation signal and a luminance signal derived from a digital color television signal. Each of the memories consists of two memory units which are alternately used for s... | 10/11/1994 |
| 5310133 | Magnetic tape transport device with tape tension roller on a lever subjected to motor torque In a magnetic tape transport device having supply and take-up reels and tape guide elements, as well as a scanner, there is engaged with the tape on each side of the scanner a tape tension roller on the free extremity of a tape tension lever which is subj... | 05/10/1994 |
| 5282021 | Video hue correction taking account of saturation and luminance A digital color television signal has its chrominance component, which is in the form of color difference signals, resolved into color hue and color saturation signals which are used to address a function memory which provides a pair of correction signals... | 01/25/1994 |
| 5278715 | Scanning device for magnetic tape with special disposition of rotary transformers for recording and playback magnetic heads For oblique track scanning of magnetic tape which is looped around a two-part drum (1, 2) separated by a gap (5) in which magnetic heads (11) affixed to a headwheel revolve, the rotary transformers connecting the magnetic heads on the headwheel to fixed p... | 01/11/1994 |
| 5276708 | Coding method for reducing the D.C. component in the data stream of a digital signal For reducing the d.c. component of a digital signal in which a good many data words are put together in data blocks each having the same number of words, a supplementary word is derived and is transmitted or stored along with the data words. The bit mix o... | 01/04/1994 |
| 5253132 | Cassette tape capstan drive with rocker above capstan for swinging pressure roller out of and into ready position and with magnet-force for pressure A tape drive mechanism for magnetic tape apparatus for tapes housed in cassettes has a pressure roller (29) at one end of a press-on lever (35) which is pivotally held on a drive shaft bearing (31) of a drive shaft (30) so that it can be inclined in a ver... | 10/12/1993 |
| 5245414 | Video signal synchronizer for a video signal in luminance and chrominance component form Video signals are supplied as component signals (in which the color signals are not correlated with a color carrier wave) and are stored in a frame memory and read out therefrom in synchronism with supplied reference signals. A FIFO memory is interposed a... | 09/14/1993 |
| 5235471 | Method of converting the data rate of a data signal A method of recording and/or playing back a data signal, in an apparatus in which a tape helically encircles a drum containing a headwheel, and the heads scan oblique tracks on the tape, features reduction of the tape velocity by a factor 1/n where n is a... | 08/10/1993 |
| 5229893 | Circuit apparatus for deriving synchronizing pulses from playbacks of a video tape recording Synchronizing pulses are separated from a video signal played back from a magnetic tape recording. The individual synchronizing pulses are then inspected in a digital inspection circuit containing two generic array logic (GAL) units and a counter, operati... | 07/20/1993 |
| 5223987 | Method and apparatus for reproducing at a selected speed video signals recorded on magnetic tape The magnetic tape video playback apparatus for a digital video signal regenerates the sample rate from the playback to operate a counter and detects the video data block numbers to permit an address generator to derive the more significant bits of address... | 06/29/1993 |
| 5218445 | System for focusing a television camera objective lens A system for focusing a zoom lens objective of a color television camera. A luminance or green video signal derived from a portion of the picture is full-wave rectified and then averaged. The sharpest focus corresponds to the highest value of that average... | 06/08/1993 |
| 5212610 | Scanning device for magnetic tape with special bearing arrangement for scanner shaft A scanning device for a magnetic tape recording and playback equipment of the oblique track type has a drive shaft (9) for a rotary head wheel (4) mounted in a duplex ball bearing (10) centered on the orbit plane of the magnetic heads which revolve on the... | 05/18/1993 |
| 5212690 | Method of synchronizing digital data by comparing to a reference word to determine bit errors A method of synchronizing digital data which includes periodic synchronization sequences. The first step in the method comprises determining the number of bit errors in relation to an ideal bit sequence in the synchronization sequence. A next step compris... | 05/18/1993 |
| 5195044 | Digital oscillator for generating a signal of controllable frequency A digital oscillator is built around an accumulator which is incremented by a predetermined number N of unit values at every pulse of a sequence of pulses of a reference frequency and the carry output of the accumulator is used to produce the output frequ... | 03/16/1993 |
| 5191419 | Video noise reducer with detection of both total and temporal picture changes A video noise reducer comprises a full picture memory and provides comparison of corresponding pixels of undelayed and delayed video signals, in which the delayed signal is fed back and mixed which is the undelayed signal at a controllable fader fading fa... | 03/02/1993 |
| 5170296 | Apparatus for reproducing magnetically recorded signals with amplitude correction Data signals recorded in oblique tracks on a magnetic tape, after they are picked up, preamplified and prefiltered, are rectified and converted to digital values representative of amplitude in respective segments distributed over track lengths. For each s... | 12/08/1992 |
| 5168349 | Synchronization of color carriers of different color TV standards having the same line frequency When two color television standards prescribe the same horizontal scanning frequency but different color carrier frequencies, one of them, for example, requiring a frequency providing a one-half line offset to the horizontal scanning frequency (NTSC Stand... | 12/01/1992 |
| 5166834 | Method and apparatus for slow-motion playback of digital video signals For reliable playback of digital video signals in slow-motion operation over a wide range of slow-motion speeds, auxiliary playback heads are positioned closely behind normal playback heads and offset by half a track width therefrom. Each of the playback ... | 11/24/1992 |
| 5148278 | Filter circuit of the median type for video signals For filter video signals a median selector is used to the inputs of which the sample values of a first pixel and other neighboring pixels. These other pixels lie in the line direction (horizontal) and in a direction perpendicular thereto (vertical) next t... | 09/15/1992 |
| 5146315 | Method and apparatus for automatically setting parameters in the derivation of a mixer keying signal from video signals In a system in which a color-controlled signal is put through a limiter to produce a video mixer signal, variable settings are provided for for color hue, color selectivity, clip level and control signal amplification. The setting magnitudes are prelimina... | 09/08/1992 |
| 5144645 | Circuit apparatus for generating a symmetrical pulse sequence of variable frequency A monostable multivibrator having a time constant that is approximately one-quarter of the period of a pulse signal supplied to its input is used for frequency doubling of a 50% keying ratio input pulse signal. The output signals of the multivibrator are ... | 09/01/1992 |
| 5142368 | Method and apparatus for changing the position of a digitally generated television special effect boundary In the generation of a digital special effect boundary signal for mixing or fading television signals with a wipe movement, the boundary position is determined by the state of a counter controlled by a clock pulse oscillator coupled to the line frequency.... | 08/25/1992 |
| 5140409 | Method and apparatus for deriving a color controlled video mixer keying signal For deriving a keying signal for a video mixer from a video pattern signal which may be derived by reference to the presence of a selected color in one of the video signals to be mixed, the level-shift voltage added to the video signal for producing the c... | 08/18/1992 |
| 5130921 | Digital controller for scanned actual condition signals Sequentially scanned digital input signals are applied to the controller to derive output signals which are formed of the sum of scanned values of the signals weighted with selected coefficients. The weighting with the coefficients is carried out by use o... | 07/14/1992 |
| 5122761 | Digital PLL including controllable delay circuit A digital oscillator clocked by clock pulses (T) produces an output rectangular wave, the phase of which is controlled by a magnitude supplied to a D register (8'). The most significant bits of that magnitude are derived from the contents of a counter (4)... | 06/16/1992 |
| 5103349 | Process for directly copying frequency modulated video signals from magnetic tape to magnetic tape A process for copying frequency modulated video signals stored on a magnetic tape includes playing back a frequency modulated carrier signal by a reproduction device having a frequency limiting characteristic which is outside the frequency modulation rang... | 04/07/1992 |
| 5097521 | Method of concealing scratch errors in a video signal derived from a film scanner Film scratches that produce errors in video signals produced by a film scanner generally run vertically over one or more moving picture frames and are particularly troublesome where they are intersected by picture contours, i.e. oblique boundaries between... | 03/17/1992 |
| 5075809 | Rotary magnetic head tape-scanning device with heads protected from cross-talk by mounting on a head carrier and by annular shielding of a portion of the head projecting from the head carrier A magnetic head affixed to the underside of a carrier body mounted at the periphery of a head-wheel for scanning oblique tracks on a magnetic tape is provided with shielding of ferrite, mu-metal or amorphous iron, to reduce magnetic crosstalk. The shieldi... | 12/24/1991 |
| 5057948 | Recording of digital signals on d.c.-erased magnetic tape In order to avoid distortion of digital signals recorded on a magnetic tape following erasure of the recording tracks by a d.c. erase head, a compensating magnetic bias field opposed to the remanent erase field is superimposed upon the field recorded by t... | 10/15/1991 |
| 5055920 | Still picture decoder for color television signals having a phase changing color carrier Color television signals obtained by scanning a still picture are converted into digital video signals and stored in video frame memory for delaying the signals. Undelayed and delayed digital video signals are added together to produce a luminance signal ... | 10/08/1991 |
| 5051847 | Magnetic head driver amplifier for oblique track recording tape A differential amplifier (15, 16) which drives a recording head and is located on the headwheel which carries the recording head is equipped with automatic switchover provided by a transistor (18) in series with a resistance and the emitters of the differ... | 09/24/1991 |
| 5043825 | Intermediate picture field storage system for slow motion playback of video tape recording For slow motion playback operation with a digital video magnetic tape recording and reproducing equipment an intermediate memory system has four picture field memories of which there are always three available for writing into but only one of them at a ti... | 08/27/1991 |
| 5040054 | Circuit apparatus for automatic correction of TV color balance For picture elements (pixels) having a luminance value in a mid-range of luminance magnitude and a color saturation smaller than a predetermined threshold value a correction signal is obtained by integration of the color saturation value followed by multi... | 08/13/1991 |
| 5040066 | Apparatus for generating control signals of a video mixer system A memory for pixel factors has somewhat more than enough capacity for storing pixel factors for all the pixels of a television picture. A special effect pattern for use in fading from one input picture to another is stored in the memory either as a contou... | 08/13/1991 |
| 5038210 | Test pattern signal generator for producing zone plate and other test patterns A test pattern generator for digital television signals produces a zone plate pattern on an orthogonal pixel raster generated by pixel and line counters. The counter outputs are supplied to respective ROMs each storing a parabolic function. Their outputs ... | 08/06/1991 |
| 5038229 | Method of performing a tracking adjustment of a digital video recording and reproducing equipment A magnetic tape recorder/reproducer for digital video signals has an error recognition circuit unit as well as circuit units for correction and/or concealment of recognized errors in the video signal. During a tracking adjustment procedure a manual contro... | 08/06/1991 |
| 5038350 | Method and circuit apparatus for data word error detection and correction In the detection and correction of errors in the decoding of data words of a series of data word blocks each provided with check words in accordance with a Reed-Solomon code the results of the necessary calculations are precomputed and stored in permanent... | 08/06/1991 |
| 5036395 | Video production facility A video production facility has a switching matrix for video signals that serves both as the usual studio switching matrix for video signals interposed between video signal sources and video signal destinations and also provides the necessary switching fo... | 07/30/1991 |
