Panasonic Technologies, Inc.

Matsushita Electric Industrial Co., Ltd.

Jerome D Shields

Kevin J Stec

Kenneth E Vavreck

Lee R Dischert

Clarence J-y Hau

A filter system that filters a digital signal to produce a filtered digital signal where the digital signal has alternating first data values and second data values. The filter system includes a demultiplexer that produces a first signal that includes the first data values and a second signal that includes the second data values. A first filter is provided to filter the first signal and the second signal to produce a first filtered signal including filtered first data values. A second filter is provided to filter the first signal and the second signal to produce a second filtered signal including filtered second data values. A multiplexer alternately selects the filtered first data values and the filtered second data values to produce the filtered digital signal.

High speed interpolation filter and a method thereof

A filter selector generates a filter address value to select one of a number of frequency characteristics of a filter to resample a first data signal from a first segment of data in order to generate second sampled data signal in a second segment of data. The filter selector includes an adder which adds a resampling factor to a previous address value to generate a current address value if the previous address value is less than a comparator value and which subtracts the comparator value from the previous address value to generate the current address value if the previous address value is greater than or equal to the comparator value. The current address value is shifted by n bits, where n is an integer, to generate the filter address value.

Interpolation filter selection circuit for sample rate conversion using

A sample rate conversion system converts from an input sample rate stream having a predetermined input sample rate to an output sample stream having a predetermined output sample rate by interpolating output samples from the input samples using first and second approximate sample rate ratios. The system includes circuitry which selects a sequence of interpolation filters from among a set of filters, the sequences being defined by one of these approximate ratios, and circuitry which monitors the magnitude of the accumulated error introduced by the approximation. When this accumulated error becomes greater than a threshold, the system changes to use a further sequence of interpolation filters based on the other approximate ratio. The accumulated error changes in a positive sense with each successive sample while one of the two approximate ratios is used. The accumulated error changes in a negative sense with each successive sample while the other of the two approximate ratios is used. The system switches between these sample rate ratios to maintain the magnitude of the position error of the interpolated samples below a predetermined threshold value. A sample rate conversion system which converts a television signal in CCIR (601) format into a Phase Alternate Line (PAL) video signal is disclosed.

Approximating sample rate conversion system

A video signal processing system uses a sequence of interpolation filters to resample a 125M video signal to produce a 244M signal. In addition, the system allows an operator to specify a desired subcarrier-to-horizontal sync (SCH) phase and a desired horizontal position. The system automatically adjusts the starting point in the sequence of filters used for the resampling operation to implement each of the requested phase shifts.

Apparatus for adjusting the timing of sampled data signals in a

A system converts digital video signals between two digital video signal formats. The system includes a rate converter which receives digital samples of the video signal in the first format and at the clock frequency thereof and converts those signls to digital samples of the video signal at the clock frequency of the second signal format. The outputs of the rate converter are combined with appropriate coefficients in a digital filter to produce alternately coefficient modified chorma and luminance signals which are combined in an output circuit to produce the digital video signal in the second video signal format.

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Atco, NJ, United States of America

Jerome D Shields