Conexant Systems, Inc.

Brooktree Corporation

Rockwell Semiconductor Systems, Inc.

Benjamin E Felts, Iii

David J Wicker

Sanjay K Jha

John E Welch

Gregory C Parrish

Michael J Brunolli

Stephen G Glennon

Matthew J DiMeo

Asif Shakeel

Havard Lee Scott

Wilson Wang

David A G Wilson

A digital FIR filter is provided that inputs a series of data samples x&lsqb;0&rsqb; . . . x&lsqb;n&rsqb; and generates a partial sum output PS&lsqb;i&rsqb;, where i&lE;n. The partial sum output is a weighted version of the a difference between a partial sum of the previous i&minus;1 data samples, PS&lsqb;i&minus;1&rsqb;, and the current data sample x&lsqb;n&rsqb; added to the current data sample x&lsqb;n&rsqb;. The filter includes a plurality of weighting stages. Each weighting stage includes a first adder for subtracting the current data sample x&lsqb;n&rsqb; from the previous partial sum PS&lsqb;i&minus;1&rsqb;, a multiplier that multiplies the difference by a weighting coefficient, and a second adder that sums the weighted difference with the current data sample. The filter also includes a plurality of delay elements, each of which inputs a partial sum and imposes a unit delay on the partial sum before supplying it to a weighting stage.

Systems and methods for a partial sum digital fir filter

A signal processing system and process for digitally filtering a single tone digital signal is disclosed. The system includes a single tone signal generator, which may or may not perform frequency modulation. The single tone signal generator receives an input signal and generates a frequency indicator which is used internally by the single tone signal generator and is also communicated to a direct realization filter. The direct realization filter uses the frequency indicator to generate a phase offset indicator, which is communicated back to the single tone signal generator. The single tone signal generator uses the frequency indicator and the phase offset indicator to generate a phase-adjusted single tone signal. The direct realization filter generates a filter gain and multiplies the single tone signal with the filter gain to produce a filtered single tone signal.

System and process for filtering single tone signals

A method for adjusting timing of a secondary system with respect to a reference system is disclosed. The secondary and reference systems include a secondary synchronization signal and a reference synchronization signal, which are used to detect a phase difference between the secondary synchronization signal and the reference synchronization signal. A filtered phase error is generated from the detected phase difference. In addition, a frequency difference is detected between the secondary synchronization signal and the reference synchronization signal, and an instantaneous frequency difference and a filtered frequency error are generated from the detected frequency difference. The filtered phase error and the filtered frequency error are accumulated, and the timing of the secondary system is controlled in accordance with the accumulated filtered phase error, the accumulated filtered frequency error, and the instantaneous frequency difference.

System for adjusting clock frequency based upon amount of unread data stored in sequential memory when reading a new line of data within a field of data

An apparatus and method for converting pixel data from a computer video format to a television-compatible composite video waveform. A color space converter converts RGB or YCrCb pixel data into YUV pixel data. The YUV pixel data is supplied to an encoder which encodes the data into a composite video waveform. A clock generator generates an encoder clock frequency based on the horizontal resolution of the incoming computer pixel data. The encoder clock frequency is sufficient to allow encoding of all incoming pixels in the active video portion of the waveform without physically scaling or altering the pixel data. Sync and burst processors in the encoder encode sync pulses and burst waveforms at proper timing intervals despite the variable encoder clock frequency by accessing sync pulse and burst waveform values and timing parameters appropriate to ranges of clock frequencies that are stored in a ROM.

Method and apparatus for horizontally scaling computer video data for display on a television

A number of methods to display interlaced video on non-interlaced monitor are disclosed. One method is to display all of the incoming fields but one at a time, and correcting for the positional offset of one field relative to another in the interlaced data. An important aspect of the present invention is the correction of the positional offset of the two interlaced video fields. There are two ways presented to deal with the vertical offset of the two fields in accordance with the present invention. The first way is that the two fields can be displayed at different positions on the display using a non-interlaced display. The second way is that the video data can be altered to correct the positional offset between the fields. Another method of the present invention is to lock the frame rate of the output video to the incoming field rate or a multiple of the incoming field rate, or to certain sub-multiples of the incoming field rate. An important feature of this method is that each frame of the output monitor need not match the incoming field time precisely. As long as each output frame is displayed exactly the predetermined number of times, the appearance of smooth motion will be maintained.

Methods and systems for displaying interlaced video on non-interlaced monitors

An adaptive signal separation system and method for quadrature amplitude modulated signals that is particularly well-suited for YC separation of a composite television signal. An adaptive approach for separating overlapping signals wherein the adaptive approach selects between notch or equivalent filtering and a comb filtering system, wherein the chrominance is first demodulated to the IQ domain prior to comb filtering. The demodulated comb filtered IQ data streams are then re-modulated to reconstruct the luminance portion of the signal.

Comb filtered signal separation

An adaptive method and system for processing luma and chroma signals from lines of a video signal. The invention includes an adaptive comb filtering algorithm that determines whether to average lines of video data based on the signal content. If two lines are dissimilar, a simple notch/bandpass system is used. The invention provides improved adaptive comb filtering performance at vertical transitions between high-luminance-detail areas and between other areas such as solid colors or flat gray or white fields by dynamically determining whether to average the chrominance information of the current video line with the chrominance information of the previous line, next line, both of such lines, or neither of such lines. In one aspect, the invention includes determining whether to average a current chroma value of a current video line with corresponding chroma values of the previous line, next line, or both of such lines, or neither of such lines; computing an output value for the current chroma value in response to such determination; determining a luminance correction from the current chroma value and the computed output value; and applying the luminance correction to a luma value corresponding to the current chroma value to correct any changes to the luma value.

Adaptive method for Y-C separation in video signals

Successive pixels representing video data in successive lines in a raster scan are buffered. Each of the lines has a sync pulse defining the line beginning. A phase adjustment is determined between the sync pulse, preferably at a particular level in the sync pulse, and an adjacent one of system adjacent clock signals at a particular frequency. The actual or expected phase adjustment between the pixels at the end of each line is also determined. The difference between the phase adjustments at the beginning and end of each line is then determined. Progressive adjustments are made in the phase of each successive pixel in the line relative to the system clock signals in accordance with the number of system clock signals in the line and the determined difference in the phase adjustment between the line beginning and end. In this way, the pixels of video data are synchronized with the system clock signals. When the actual phase adjustment relative to the system clock signals is determined at the end of each line, the difference in the phase adjustments at the beginning and end of such line is determined from the phase adjustment for such line and the phase adjustment stored for the previous line. When the expected phase adjustment is provided for the end of each line, this estimated value is altered for each line by an amount equal to the actual phase adjustment at the beginning of such line and the estimated phase adjustment at the end of such line.

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Cardiff, CA, United States of America

Benjamin E Felts, Iii