Abstract: Individual frames in a video signal are encoded using different coding techniques such as intraframe, motion compensated prediction and motion compensated interpolation coding. The encoder output, which is produced at a first highly variable rate, is applied to a channel via a buffer that outputs the encoded signal at a second, less variable rate. The rate allocated to different frame types is determined as a function of the type of frame being encoded and the coding technique being used. A second buffer may be used to eliminate almost all variations in the rate at which data is applied to the channel. Buffer fullness may control characteristics of the encoder such as quantizer step size and/or prefiltering.

Abstract: A video processing system is disclosed that separates and separately encodes and decodes the low and high spatial frequency coefficients of images for transmission or storage. Each block of an image is transformed into the frequency domain. High frequency coefficients of the resulting transform matrix are separated from the low frequency coefficients. The low frequency coefficients are motion prediction compensated to derive motion vectors and a prediction error signal. The motion vectors, prediction error signal and high frequency coefficients are channel encoded for storage or transmission. In a receiver, the motion vectors and prediction error signal are used to reconstruct a low frequency motion-compensated version of the image. The high frequency coefficients are inverse transformed into the pel domain and are combined with the reconstructed low frequency verison of the image to reconstruct a version of the original image.

Abstract: Motion digital video is encoded and decoded by a motion compensated interpolation method and apparatus. In accordance with the method, selected frames of the video are interpolated in the decoder with the aid of interpolation correction codes that are generated in the encoder and sent to the decoder. In an encoder embodiment that interpolates half of the frames, every other frame is encoded and decoded within the encoder. The decoded versions of adjacent frames are appropriately combined and compared to the interleaved camera frame that is to be interpolated in the decoder. The differences, which correspond to "pels correction" information, are encoded and quantized. Those that exceed a predetermined threshold value are added to the encoder's output buffer. The inverse operation is carried out in the decoder. That is every pair of decoded frames is averaged and combined with the decoded "pels correction" information to form the interpolated frames.

Abstract: The bandwidth required for a regularly occurring signal such as a television signal, as received from a signal source can be substantially reduced by not transmitting each and every one of the horizontal scan lines. Rather, firstly, one or more selected lines may be transmitted and, secondly, instead of transmitting the remaining, unselected lines, a signal representing a predetermined arithmetic difference among predetermined ones of the scan lines may be transmitted.

Abstract: The present invention relates to a Time Compression Multiplexing (TCM) technique for transmitting three consecutive television picture signals from a television picture source during the time period normally used to send one television picture signal. More particularly, three consecutive lines or fields from a TV signal source are compressed into an ordinary line or field period, respectively, by sending one line or field as is, but time compressed, in one portion of a line or field period and sending two other lines or fields as differential signals, also time compressed, to occupy two separate and different portions of the same line or field period as is used by the first one line or field. With such technique it is possible to send three consecutive line or field signals from each of three separate colocated or non-colocated TV sources on a Time Division Multiple Access (TDMA) basis.

Abstract: The bandwidth required for a regularly occurring signal, such as a television signal, as received from a signal source can be substantially reduced by not transmitting each and every one of the horizontal scan lines. Rather, firstly, one or more selected lines may be transmitted and, secondly, instead of transmitting the remaining, unselected lines, a signal representing a predetermined arithmetic difference among predetermined ones of the scan lines may be transmitted. The bandwidth may be further reduced by a time expansion of the time interval of the selected line signal and by a time compression of the time interval of the differential signal. The bandwidth required for each regularly occurring signal as received from each of a plurality of N signal sources may be more efficiently used by time compression multiplexing the respective time expanded and time compressed signals.

Abstract: The present invention relates to a technique for the Time-Frequency-Multiplexing (TFM) of three television signals. More particularly, three fields of a TV signal are sent simultaneously to a remote receiver by transmitting one field as is in the baseband of a standard television system signal while the other two fields are transmitted as differential signals, quadrature amplitude modulated onto a subcarrier frequency above baseband. The two differential signals can comprise two field differential signals or a frame and a field differential signal. Arrangements are also provided for transmitters and receivers for implementing the present technique.

Abstract: The present invention relates to a near-instantaneous companding coder wherein the peak a-c amplitude of an input signal is measured over a block of K samples. Each of the K samples is coded into an n-bit quantized sample code word based on a step size quantizing control signal determined from the measured peak a-c amplitude. The step size quantizing control signal, and other overhead information such as parity, sync, etc., are formed into a K-bit overhead word and transmitted serially by adding a separate bit of K-bit overhead word to each of the corresponding K n-bit quantized sample code words associated with an immediately prior block of K sample code words. At the remote decoder, the received K-bit overhead information word is stored and used to decode the next subsequent block of K received n-bit quantized sample code words.

Abstract: The present invention relates to a technique for the synchronization of multiplexed television signals within each burst signals received at a remote station or satellite in a TDMA communication system from non-colocated ground stations. The technique employs a dynamic master/slave ground station arrangement where a first station signing on assumes the role of the master ground station. Other stations subsequently signing on synchronize their transmissions to the master station signal burst or the signal burst of the last station to sign on by using apparatus which monitors the received burst from the remote station, measures its own signal delay to the distant station and then phase-locks its local subcarrier clock to the master or last station's transmission burst. Dynamic transfer to the second station signing on occurs when the current master station terminates transmission for any reason.

Abstract: The present invention relates to a technique for generating a Semi-Compatible High Definition Television (SC-HDTV) signal which can be sent over two present-day Cable Television (CATV) channels. In accordance with the present invention, a HDTV signal is formed comprising a line scan rate which is a multiple of the line scan rate of a current conventional TV signal. The SC-HDTV signal is formed therefrom by transmitting a first HDTV line as is and a second HDTV line as a field differential signal transmitted via QAM on the IF or RF carrier of the first line signal at a line scan rate of a current conventional TV signal. Arrangements are also disclosed frDconverting the SC-HDTV signal back into either a HDTV or conventional TV signal.

Abstract: The present invention relates to a compatible high-definition television (CHDTV) color picture signal which is capable of conversion by simple and inexpensive means into either a HDTV composite color picture signal for use by a HDTV receiver or an associated conventional television system (ACTS) color picture signal for use by an ACTS receiver. The present CHDTV color picture signal comprises (a) a first line scan rate which is the same as that of the ACTS signal, (b) a first line signal of a HDTV camera signal produced at a second line scan rate which is time stretched and transmitted as is at the first line scan rate in a first portion of the CHDTV signal bandwidth, and (c) a second line signal of the HDTV camera signal which is time streched and transmitted as a line differential signal on a vestigial sideband carrier signal in a second portion of the HDTV signal bandwidth.

Abstract: The present invention relates to a spread spectrum, FH-MFSK radio receiver capable of demodulating and decoding one or more concurrently received L-length frequency-hopping, Q level frequency shift keyed signals to determine the correct signal of a particular user. In operation, the receiver spectrum analyzes the received signal to determine which frequency components are present during each of the L chip intervals and then demodulates a particular user's L-length FH address signal with the derived frequency components to arrive at a Q by L-length detection matrix. A detector and checking processor determines which L-length matrix rows have a maximum number of entries and if only one such row exists, that level is deemed the correct message level. Where multiple maximum-length rows are found the processor uses the address sequences of all other users to check if the row entries could have been caused by interference. The row with the minimum matches is deemed the correct message level.

Abstract: Bandwidth is a precious resource in a communication system. High frequency signals, for example, video signals, typically require a relatively large bandwidth. One means for reducing bandwidth is by way of time compression multiplexing wherein signals may be stored a short period of time, compressed in time and then transmitted over a communication path. The subject signal processor may time compress and time synchronize an input signal with a time multiplexed signal. In a first arrangement, responsive to a time delay difference between the signals (215), a first frequency signal (220) is used to modulate (230) the input signal (210). The modulated signal is extended through a dispersive filter (260) for introducing a delay to the input signal, the delay for synchronizing same with the time multiplexed signal. The synchronized output of the dispersive filter may be extracted by an envelope detector (270) for extension to an output terminal (280).

Abstract: Frequency and time division multiplexing arrangements are common for efficiently utilizing bandwidth in a communication system. Still another, lesser known arrangement is called time compression multiplexing. In time compression multiplexing, a signal from each input channel is stored for a short period of time. The signals from all channels are then read from the store, compressed in time and transmitted over a communication path to a receiver. Unfortunately, the art appears to be remiss in the time compression multiplexing of video signals. The subject signal processor includes a plurality of input terminals (111, . . . , 11N), each input terminal being adapted to receive a video signal, each video signal including a plurality of scan lines, each scan line having a time duration T seconds. The signal processor also includes an arrangement for compressing a video signal by a factor M (illustratively M=N). More specifically, the signal processor compressing arrangement includes apparatus (120, 131, . . .