Abstract: Chrominance phase error correction circuitry includes a demodulator for demodulating a received video color burst signal into first and second demodulated signals and signal generation circuitry for providing to the demodulator a demodulating signal for demodulating video color burst signal. Phase correction circuitry detects a phase error from the first and second demodulated signals and varies a phase of the demodulating signal to provide a corrected demodulating signal for demodulating a video chrominance signal with the demodulator during an active video period.

Abstract: An adaptive circuit and method for separating luminance and chrominance components from a composite video signal by deriving three input lines from the composite video signal, determining whether any luminance similarity exists among the three input lines, and then selectively enabling a component filter based on any luminance similarity. If no luminance similarity exists among all three of the input lines, then a subtractive comb filter is enabled to maintain high vertical luminance resolution. If luminance similarity exists among all three of the input lines, then an additive comb filter is enabled. The additive comb filter performs three-line averaging when a high degree of similarity exists among all three consecutive input lines to minimize cross-chroma artifacts on lines that are similar.

Abstract: A method and apparatus for maintaining an ideal frequency ratio between numerically-controlled frequency sources provides a mechanism for maintaining coherence between multiple synchronization references where a known ideal rational relationship between the sources is known. Multiple numerically controlled oscillators (NCOs) generate the multiple synchronization references, which may be clock signals or numeric phase representations and the outputs of the NCOs are compared with a ratiometric frequency comparator that determines whether there is an error in the ratio between the NCO outputs. The frequency of one of the NCOs is then adjusted with a frequency correction factor provided by the ratiometric frequency comparator. The NCO inputs can represent ratios of the synchronization reference frequencies to a fixed reference clock and the NCOs clocked by the fixed reference clock.

Abstract: Video decoder systems in which both the analog-to-digital converter and the composite decoder are driven by the stable sample clock, such as a crystal source. The outputs of the composite decoder are provided to a source rate converter, having an output that is provided to a digital output formatter. The digital output formatter is driven by the output clock, which may be locked to the source clock if desired. The output clock is developed by a clock generator which may be one of several different types, including a fractional N synthesizer, a direct digital synthesizer or a puncture clock.

Abstract: A video decoder in which the video source clock is generated entirely in the digital domain is disclosed herein. By creating a virtual version of the source clock in a numeric oscillator, the amount of noise in the system is substantially reduced. Furthermore, by transferring the digitized video signal, sampled with an asynchronous crystal clock, into the source clock domain, the accuracy of the brightness (amplitude) and color (phase) information can be greatly enhanced.

Abstract: A communication device such as a mobile station (410) for a spread spectrum communication system includes a receiver (100) having an adaptive equalizer (104) which suppresses interference on a received spread spectrum signal to produce an equalized signal (126). A pilot channel demodulator (110) demodulates the equalized signal to produce an estimate of the pilot channel (140). A summer (112) compares the pilot channel estimate and a predetermined data pattern to produce an error signal (124). A traffic channel demodulator (108) demodulates the equalized signal to produce one or more traffic channels.