Abstract: A system for determining the sequential position of video fields of a received video signal that was derived from a film having successive image frames in accordance with the 3:2 pulldown method, wherein the video fields are produced at a greater rate than the film frame rate and in a predetermined repetitive sequentially varying relationship to the film frames wherein at predetermined positions in the sequence a video field is identical to the video field that preceded it by the duration of two video fields. The system includes means for delaying each field of the received video signal; means for comparing each received video field with a video field that has been delayed by the duration of two video fields; and means for comparing the results of a successive number of said comparisons with the predetermined sequence to determine when identical fields are located in only said predetermined positions in a sequence of the compared received video fields.

Abstract: Extended horizontal definition is provided in a television system in which the wideband and narrowband chrominance components of a video signal are modulated for transmission by a subcarrier. The modulated wideband I chrominance component is filtered over a bandwidth that is antisymmetrical about the subcarrier frequency with an extended upper sideband to thereby entend the bandwidth that is available for transmission of the I chrominance component. The modulated I chrominance component is antisymmetrically filtered to enhance the relative amplitude in the extended portion of the upper sideband for transmission, and in a television receiver the modulated I chrominance component of a received video signal is filtered to have a relatively flat-response over the antisymmetrical bandwidth about the subcarrier frequency.

Abstract: A receiver interface system for enabling an operator to access different types of services in a like manner, wherein the services contain different combinations of service components received by a receiver in different portions of one or more different frequency channels, such as television channels. The system includes a plurality of separate interface channels for carrying different types of services containing different combinations of the service components; switching means for selecting a said service, wherein the switching means is coupled to the interface channels for accessing the respective interface channels in a like manner; and a decoder coupled to the receiver and the interface channels for accessing the components of said selected service received by the receiver in different portions of one or more different frequency channels to provide said selected service on the interface channel carrying the selected service.

Abstract: A system for companding digital audio signal samples processes the digital audio signal samples to correct errors induced by the compression and expansion processes. These errors are calculated prior to compressing the samples. Such errors are calculated in accordance with a predetermined compression process and a predetermined expansion process; and the digital audio signal samples are corrected in accordance with such calculations prior to compression. The compression process includes providing a 3-bit gain word for a block of 70 samples. The gain word is computed in accordance with the position of the most significant "1" bit in the sample(s) having the peak magnitude. Each individual sample is processed in accordance with the block gain word to compress the sample by reducing the number of magnitude bits.

Abstract: A system for scrambling a video signal having a plurality of horizontal lines, each of which includes a video information portion and a non-video information portion. The scrambling system includes a memory; means for storing the video information portion of each video signal line in the memory; and means for forming scrambled horizontal lines by retrieving each of a plurality of said stored video information lines in a plurality of segments preceded by a non-video segment and separated by non-video segment(s). The retrieval means include means for varying the respective durations of the retrieved video information segments in individual scrambled horizontal lines in accordance with an encryption keystream; and means for varying the total duration of the non-video segments for individual scrambled horizontal lines in accordance with a predetermined timing pattern. A complementary descrambling system also is disclosed.

Abstract: A system for regenerating a standard-length color burst signal from a less-than-standard-length color burst information signal of a given frequency and phase. The system includes a phase-locked loop for generating a system clock signal from the color burst information signal, with the clock signal having a clock frequency related to and at least twice the given frequency of the color burst information signal. The phase information from the color burst information signa is sampled and stored in a RAM. The sampling is clocked by the system clock signal. A standard-length color burst signal is regenerated at the given frequency and in phase with the color burst information signal by retrieving the stored phase information and extrapolating the standard-length signal in accordance with the retrieved phase information. Such retrieval is clocked by the system signal.