Abstract: To improve the perceived audio signal, it is known to use a harmonics generator to create the illusion that the perceived audio includes lower frequency signal parts than really available. In addition to improving the perceived so called ultra bass signals (for example 20-70 Hz) also the signals in the frequency band between the ultra bass signal and the normal audio signal are improved.

Abstract: A sound-reproducing apparatus comprises an acoustic horn which terminates in an opening in the wall of the apparatus. An obstacle is arranged in the acoustic duct of the horn, which provides a better frequency response.

Abstract: A picture signal source (PSS) comprises an encoding circuit (ENC) for encoding a picture signal having a higher bandwidth to a picture signal having a lower bandwidth. Encoding is effected in dependence upon the extent of motion in the picture which is determined by a motion detection device (MOT). An encoding has been given as an example, using several picture signal channels (PC1, PC2, PC3) each having a different picture signal refreshing period of, for example 80, 20 or 40 ms. The so-called field skipping method is used for which a switching circuit (SC4) switching at the frame frequency is provided. The picture display device (PDD) comprises an essentially complementary, inversely operative decoding circuit (DEC) with a motion-compensated (VR') picture signal interpolation circuit (MEM, INT, G) which comprises a gamma compensation circuit (G) according to the invention. Without this circuit a troublesome area flickering may occur upon display in practice.