Abstract: A filter using analog to digital conversion, digital filtering and oversampling noise reshaping is disclosed. Application of such a filter to a frequency locked oscillator is disclosed. Application of such a filter to an oscillator having a capability to synchronize with an external stimulus is disclosed.

Abstract: A method and/or apparatus is capable of performing high accuracy digital level restoration with a high degree of noise immunity provided by a passive clamping stage.

Abstract: The present disclosure describes a technique that allows the amplitudes of vertical correction signal components to be adjusted independently. When the amplitude of each of the vertical correction signal components are set, they will not have to be readjusted when the amplitudes of the other vertical correction signal components are set. This greatly simplifies the process of setting the amplitudes of the vertical correction signal components, saving time and increasing the accuracy of the settings.

Abstract: A method and apparatus for separating a signal uses a low pass filtering in a first direction to produce a signal with a low component and a alias component and then uses a filtering in a second direction to produce a component of a separated signal. The filter has applications in television signal decoding and has other applications.

Abstract: A phase locked loop is described for generating an output clock signal that is both synchronizing with a synchronizing signal and oscillating at substantially the same frequency as required by the system. The phase locked loop as disclosed compares the time durations of the output clock of a voltage-controlled oscillator with the system clock for N cycles. A correction signal is then generated by comparing these two time durations, and the correction signal is fed back to the voltage-controlled oscillator to eliminate the difference in the time durations. In addition, the voltage-controlled oscillator is also synchronized with the synchronizing signal by using the synchronizing signal as a reset.

Abstract: By reducing the saturation (amplitude) at changes in the hue (phase) of the chrominance subcarrier of a video signal, the phenomenon of "dot crawl" can be substantially reduced for graphic data. It has been found that large hue (phase) changes associated with graphic data can cause large frequency shifts of the chrominance subcarrier resulting in a substantial portion of the chrominance subcarrier being unsuppressed by the chrominance subcarrier rejection filter of the luminance decoder. By reducing the saturation during the hue transition, the intensity of the spurious luminance information of the non-suppressed chrominance subcarrier is reduced.

Abstract: A phase locked loop is described which uses a first and second voltage-controlled oscillator. The first voltage-controlled oscillator is input into a feedback circuit which is used to produce a control signal. The control signal runs both the first and second voltage-controlled oscillators. A synchronization circuit is used to synchronize the first voltage-controlled oscillator with the synchronization pulse. In one embodiment, the synchronization circuit can use the second voltage-controlled oscillator to produce a timing interval to control the turning on and off of the second voltage-controlled oscillator in order to facilitate this synchronization. Because the output of the first voltage-controlled oscillator is sent to the feedback, the output of the phase locked loop will not drift due to parameter differences between the first and second voltage-controlled oscillators.

Abstract: A reconfigurable infinite impulse response low-pass filter is described in which the frequency response can be changed by changing a single parameter while the filter gain of the filter remains constant, preferably, unity. The parameter value is used to calculate the coefficients for the infinite impulse response filter. By choosing the parameter values carefully, the infinite impulse response filter can be implemented using shift registers rather than multipliers to reduce the hardware complexity of the infinite impulse response filter.

Abstract: By forming a digital video processor and digital television controller on the same integrated circuit, a number of advantages in improved picture quality can be obtained. The length of the communication connections between these two elements can be reduced, thus reducing television picture distortion caused by electromagnetic interference. Additionally, the elements can be controlled by a single dot clock generator with a single phase locked loop circuit. Also, register banks can be used for intercommunication between the television controller and the video processor rather than the communication between two different ICs over a bus.

Abstract: In a video encoder, the color distortion between pixels can be reduced by encoding the hue transition to limit very large hue (phase) transitions and encode a corresponding smaller phase transition. This produces fewer spurious colors between pixels during the encoding. This can be done by comparing the change in hue value to a reference value and adding or subtracting 2 .pi. to this reference value to reduce the absolute value of a modified delta hue signal.

Abstract: A digital amplitude and phase detector for detecting the amplitude and phase of a color burst digital signal used in television systems is provided. The detector comprises a phase lock loop circuit for detecting the phase of said color burst signal and for generating a synchronous constant amplitude sinusoidal signal; multiplying circuit for generating a product signal by multiplying the color burst signal by the constant amplitude sinusoidal signal, wherein said product signal has a high-frequency component and a low-frequency component having an amplitude substantially proportional to that of the color burst signal; and low pass filter circuit coupled to said multiplying circuit for filtering said product signal such that the high-frequency component is substantially suppressed relative to that of the low-frequency component. A video encoder using the digital amplitude and phase detector is also provided.