Abstract: An apparatus and method for the extraction of vertical interval time code (VITC) included in the vertical blanking interval of a television signal reproduced from video tape transported past a rotating transducer over a wide range of speeds. VITC information is extracted at a rate derived from the rate of a control signal having a rate proportional to the velocity at which the tape is transported past the transducer.

Abstract: An apparatus and method for generating a rotating clock video wipe from two voltage ramps. The voltage ramps are rotated according to rotation data supplied by a controller. The rotated ramps are combined and fed to an output signal generator and then a video mixer.

Abstract: Velocity errors in a video signal are sampled at scan line rate and are averaged over a selected plurality of frames to enhance the repetitive velocity errors while cancelling the random velocity errors. The resulting separated repetitive velocity errors then are subtracted from the initial combined velocity errors to provide separated random velocity errors. A repetitive error interlace technique is used to generate an improved repetitive error frequency control signal, while a second order correction technique provides a corresponding random error frequency control signal. The two frequency control signals are combined and the combined signal is used to provide compensation for the initial velocity errors.

Abstract: A deskew processor includes first and second memory units each having independent data write control circuits and data read control circuits. The write control loads successive data into respective memory units as it is received, and the read control reads the data out of the memory units into a data selector circuit as determined by a data selector control circuit. The latter determines the presence of any data overlap and delays read out of data via the data selector circuit until the previous data is completely read, thereby deskewing the successive data.

Abstract: A VTR controller provides an internal counter which counts a frame reference to provide a number representing the position of the reference in the video color sequence. This numbr must be synchronized to the color sequence of the station reference in order to be useful. To synchronize the internal counter in an automated system, the controller places the VTR into color framed playback mode and, after a sufficient period of time, the position of the current time code value in the color sequence is computed. The position is the value that the internal counter should have at that instant in time. The value is loaded into the counter and its output is the color frame sequence number. In a manual embodiment, an operator makes a test edit with the VTR color framer off, to determine if the value in the internal counter is correct and, if not, corrects the value. Prior to the actual edit process, another computation is performed to determine the start of the time lines which control the edit process.

Abstract: In a tape drive system, a dynamic brake control circuit provides dynamic braking for slowing and stopping an associated tape reel and motor system in the event of a power failure. Upon sensing a power failure, the electrical energy stored in a capacitor supplies electrical energy to enable the control circuit, which in turn supplies a controlled conductive path for the flow of a dynamic braking current due to the back electromotive force signal generated by the motor, to effect the controlled dynamic braking of the drive motor to a stop.

Abstract: An apparatus and method for generating waveform signals for the production of a variety of borders for video wipes by varied processing of the output of a ramp generator.

Abstract: A digital time base corrector for correcting time base errors of the digital samples of a video signal for all the various speed modes of a reproducing apparatus. The time base corrector is configured having a small capacity memory and a large capacity memory wherein the small capacity memory is divided into a first section and a second section. The first section of the small capacity memory retimes data samples for subcarrier phase errors without losing or repeating data, while the second section of the small capacity memory retimes data for horizontal frequency error without losing or repeating data in all reproducing modes except shuttle. Further, the second section of the small capacity memory in reverse and forward shuttle retimes the data for horizontal frequency and phase errors while equalizing the data rate through the time base corrector by selectively discarding or repeating horizontal lines based on line type.

Abstract: An adaptive dropout compensator is fully digital and employs an adaptive logic circuit to detect dropout characteristics such as the extent thereof and the best available replacement data, and generates an adaptive logic decision for supplying the optimum replacement data. The circuit configuration lends itself to a switchable implementation for accommodating the various color television standards.

Abstract: Video channel combines are produced by digitally processing binary numbers representing values of video image information in multiple channels, for corresponding points in a display of the resulting composite video image. The binary numbers are combined in the course of processing in response to processed key signals which determine a preselected percentage of each binary number's value, to produce new binary numbers. After summation, the latter represent composite video image values to be displayed at the same temporal and spatial locations of the display of the composite video image. Total percentages resulting from the summation of all numbers for each composite video image value, including numbers corresponding to percentage of background video, is equal to 100%.

Abstract: A bar code reader system includes a stream of pulses whose period is a function of the scan speed of the reader as it scans the bars and spaces of a bar code symbol. Transition pulses are supplied which identify the boundaries of the bars and spaces. The tach pulses which occur between transition pulses are counted, loaded into memory, and are read from memory via microprocessor means, whereby the widths of the bars and spaces are determined. The sequence of the bar and space data is decoded to yield the bar code encoded numbers.

Abstract: Apparatus for tensioning tape extending between two reels in a tape transport system having servos for controlling the velocity and position of the reels, includes position servo loop for maintaining the first reel in a fixed position. A velocity servo loop controls the other reel for taking up slack in the tape between the reels and applying a relative force on the tape once the slack has been taken up. The velocity servo is limited in the amount of current applied to the motor driving the take up reel by a signal provided by a tension servo connected to the position servo associated with the other reel. In particular, the tension servo responds to the amount of current applied by the position servo for applying a motor-current-limiting signal to the velocity servo system. When the position servo is applying minimal current to the fixed-position reel (when the tape is slack), a relatively large amount of current is allowed to go to the take up reel.

Abstract: A noise immunity circuit incorporates a first channel for tracking a train of periodic sync pulses and for locking a window to said pulses for rejecting spurious noise signals. A second channel senses when the sync pulses are displaced in phase and establishes a new rephased window that is in phase with the displaced sync pulses.

Abstract: In a tape transport apparatus, a first servo feedback loop is provided for correcting tape tension by adjusting the rotation of a tape reel in response to the sensed position of a tension arm that engages the moving tape. A second feedback loop senses the rate of change in the position of the tension arm and responsively damps the tension arm position changes by means of a lead circuit which causes a torque motor coupled to said pivotable arm to move in opposition to the tension arm position changes.

Abstract: An optical sensing circuit useful for detecting the end of a moving tape in a tape transport includes a light source and a light sensor which are closely spaced across a gap. The radiation output of the light source is modulated at a selected frequency which is determined by the operating frequency of a frequency detector. In the absence of a light obstruction, such as passage of the tape in the optical path between the light source and the light sensor, the modulated output from the light source is detected by the sensor. The processed signal from the sensor, which is characterized by the modulation frequency, is applied to the frequency detector. The detector recognizes only those signals having the modulated frequency, and does not respond to signals of different frequencies, which may result from impingement of other radiation than that from the light source on the photosensor.

Abstract: An apparatus for controlling the phase of a video data signal to effect color correction includes a video data memory and memory control circuit. Interlaced write and read portions of the memory cycle are selectively spaced in time within a memory read/write cycle to enable shifting the read portion by a selected fraction of the memory read/write cycle without affecting the write portion, whereby color correction is achieved.

Abstract: A video signal correction circuit of a signal processing system includes means for determining the chroma line type, for inserting the line type information in the video signal, and for extracting the line type information from the video signal downstream to allow selecting the phase of the chroma subcarrier to match the phase of the output station reference.

Abstract: A frequency measuring circuit measures the period between successive pulses of an input signal and converts the pulse count to a measured frequency value. The measured frequency signal is filtered to eliminate spurious noise and a variable threshold is generated by comparing the measured frequency and the filtered frequency. Only frequency signals qualified by the variable threshold are accepted as valid and provided as the output.

Abstract: A digital effects unit is integrally combined with a video switcher apparatus by interrupting various selected video signal and control paths in the switcher and, in particular, the mix effects signal from the first mixer and the pattern signal from the pattern generator, and re-routing the corresponding signals to respective inputs of the digital effects unit. The resulting manipulated video and key output signals therefrom are supplied to a second, downstream mixer which combines the digital effects with conventional switcher effects.

Abstract: A digital effects loop is inserted in the video and key signal buses which extend to a mixer of a switcher apparatus, and a digital effects unit is coupled to the loop. Circuitry is included in the loop to interrupt the particular bus or buses and the signal or signals are re-routed to provide inputs to the digital effects unit. The latter supplies transformed video and/or key signals back to the continuation of the respective interrupted bus or buses, and then to the mixer to be used thereby in place of the original signals.