Abstract: A television signal receiver processes a television signal representing a letterbox image display format with a main image region, and a bar region containing auxiliary information to help convert from interlaced to progressive scanning. The auxiliary information is processed in a signal path including a nonlinear amplitude expander and apparatus for modifying the operation of the signal path as a function of the noise content of the television signal.

Abstract: A film/video detector includes circuitry for generating the differences between corresponding pixel values in successive frames of video signal. These differences are accumulated over respective frame intervals. Accumulated values for respective frames are applied to a signal averager and to a correlation circuit. Average values from the averager are subtracted from correlation values from the correlation circuit, and film mode signal is indicated if the latter differences are greater than a predetermined value.

Abstract: A television receiver processes a television signal representing a letterbox image display format with an image region, and a bar region containing "helper" information to help convert from interlaced to progressive scanning. An image signal processing path contains a motion detector and switch for determining whether a video processor receives image information (in the presence of motion), or field repeated information (in the absence of motion). Another motion detector associated with helper signal processing exhibits a narrower motion spreading characteristic than the motion detector in the image path, and determines when the helper signal is coupled to the image path.

Abstract: A television signal receiver processes a television signal representing a letterbox image display format with a main image region, and a bar region containing auxiliary "helper" information to help convert from interlaced to progressive scanning. In the presence of image motion, a main image component and the helper component are combined and conveyed to a video processor. In the absence of motion, other image information, e.g., field repeated information, is conveyed to the video processor. The information conveyed to the video processor is determined by a switching network responsive to an control signal from a motion detector which senses low frequency luminance image information substantially exclusive of high frequency image information.

Abstract: A multimode comb filter for comb filtering, e.g., NTSC and/or PAL video signals includes delay means for concurrently providing video signals representing first, second and third adjacent horizontal lines. First and second combining means coupled to the delay means provide alternate 1-H comb filtered signals in both the NTSC and PAL modes. Control circuitry coupled to the delay means generates a control signal for adaptively selecting the one of the alternate 1-H comb filtered signals or appropriate proportions of both alternate 1-H comb filtered signals to form an output comb filtered signal. In the NTSC mode the control circuitry generates the control signal from sums of vertically aligned pairs of samples from said first and second lines and from said second and third lines. In the PAL mode the control signal is generated from alternating sums and differences of vertically aligned pairs of samples from said first and second lines and from said second and third lines.

Abstract: A multimode comb filter for comb filtering, e.g., NTSC and/or PAL video signals includes delay means for concurrently providing video signals representing three adjacent horizontal lines. First and second combining means coupled to the delay means provide alternate 1-H comb filter signals in both the NTSC and PAL modes. Control circuitry coupled to the delay means generates a control signal for adaptively selecting the one of the alternate 1-H comb filtered signals or appropriate proportions of both alternate 1-H comb filtered signals to form an output comb filtered signal.

Abstract: Comb filter apparatus for comb filtering NTSC or PAL video signals includes sampling circuitry to sample the video signal at 45 degrees relative to the I,Q or U,V axes. The sampled signal is coupled to delay circuitry arranged to concurrently provide video samples from three successive horizontal lines, designated top, middle and bottom. The video samples from the middle line are combined with samples alternately selected from the top and bottom lines to provide a comb filtered signal.

Abstract: A method and apparatus for determining the value of a sample having a particular position in an ordered ranking, by magnitude, of a set of digital samples includes means for truncating the lesser significant bits of the samples. Further means compares the values of the truncated samples and generates selection control signals indicating the truncated sample which is in the desired position of an ordered ranking of the truncated samples. A function generator then generates a function of the samples, corresponding to the selected truncated samples.

Abstract: An adaptive median filter system is disclosed. Circuitry is arranged to produce successive sets of samples from an input signal which may possibly include noise. An adaptive median filter filters the samples in response to a control signal. Further circuitry estimates the relative density of the noise in the input signal to generate the control signal supplied to the adaptive median filter.

Abstract: An automatic color burst magnitude control (ACC) for a digital television receiver is compatible with and is unaffected by variation of the phase of the color subcarrier signal introduced in demodulating the color subcarrier to effect control of tint. ACC is effectuated by digital gain control for scaling the digital words representing the sampled magnitudes of the color subcarrier burst signal. Quadrature demodulation of the color subcarrier signal produces color signal digital words I and Q which are each sampled and latched during the color subcarrier burst. The averages of the sampled I and Q digital words are applied as respective portions of the address of a read only memory (ROM). The ROM provides error words indicating whether the chroma burst amplitude is too large or too small. A control device responds to the error word to scale the color subcarrier digital words, and therefore scale the chroma burst amplitude to a predetermined magnitude.

Abstract: The IF portion of a television receiver includes a surface acoustic wave filter comprising at least two conductors having electrodes extending therefrom to form comb-shaped elements mounted on one surface of a piezoelectric substrate. Respective electrodes of the comb-shaped elements are interleaved in alternated relationship to form a transducer for launching an acoustic signal along the surface of the substrate in response to an electrical signal coupled between the two conductors. The overlap of each pair of alternated electrodes is substantially uniform throughout the transducer. The transducer includes two end portions and a center portion between the end portions. However, because the location of the center of each pair of alternated electrodes from the location of the center of an adjacent pair of alternated electrodes is substantially the same throughout the transducer, the transducer is continuous.