Abstract: In a method of transmitting and receiving Multiplexed Analog Component (MAC) television signals by producing first chrominance component and luminance component signals representing lines of a television signal capable of reconstruction in a conventional MAC television receiver to produce a first television picture having a first aspect ratio and a first number of lines and wherein the component signals for each line are time-compressed and placed sequentially at times appropriate to allow reconstruction of the television picture but occupying less than the whole line time, the improvement whereby further luminance component and chrominance component signals are generated and added to portions of the television signal not containing the first signals such that the further component signals are capable of being reproduced together with the first signals to produce an extended definition picture with the further component signals not interfering with the picture reproduction from the first chrominance and lumin

Abstract: A device for detecting co-channel interference in transmitted signals having sync pulses is disclosed, characterized in that the detected interference may be measured. The apparatus includes a detector for detecting the sync pulses, and measuring apparatus for determining a change in amplitude of the sync pulses. The measuring apparatus comprises a sampling device responsive to the detector for producing a signal indicative of the amplitude of each sync pulse. A first output is produced indicating the sum of two successive signals and a second output is produced indicating the difference of two successive signals. An analogue to digital converter produces a digital representation of each of the first and second outputs, respectively, which representations are converted to digital signals an arithmetic device. The digital signals are indicative of the magnitudes of the signals produced by the sampling device. A subtraction device subtracts the digital signals from each other to produce a control signal.