PALplus

Abstract: The removal of ghosting from received television pictures requires that a known ghost cancellation reference (GCR) or training signal be incorporated in the transmitted signal. A range of possibilities for ghost cancellation for 625 line systems has been examined within the European PALplus consortium, although it was subsequently decided that ghost cancellation should not be a standard feature of PALplus, or indeed confined to PALplus. This and further development work has led to the definition of a ghost cancellation reference signal that is believed to be suitable for all 625-line PAL, PALplus and SECAM transmission systems. The GCR is placed on a single line of the vertical blanking interval, line 318. The GCR belongs to the same family of waveforms as the GCR that has been standardized for use in North America for 525-line NTSC. This gives the potential for the development of common ghost cancellation circuit elements. Experimental ghost cancellation circuitry has developed which makes use of the GCR to enable performance to be evaluated with 625-line systems under a variety of reception conditions. The ghost cancellation techniques may be applied to improve the performance of broadcast transmitter chains, and can also be employed in consumer receivers.

Abstract: The implementation of the video signal processing of a PALpIus decoder is presented. The principle and features of the PALplus transmission system are reviewed and the operations required in the decoding described from the implementation point of view. The architecture and the programming of the scanline video processor are given. The video signal processing operations in the PALplus decoding, namely motion adaptive colorplus, inverse letterbox conversion and helper processing, are implemented using two processors. The suitability of the processor and potential and useful extensions for the processor are discussed. >

Abstract: Upon reproduction of a television signal, when wide screen signalling (WSS) data is supplied from a reproducing unit to a microcomputer, it is detected that the reproduced signal is a PALplus signal and an LED is illuminated. Thus, reproduction of the PALplus signal can be notified to the user. On the basis of control of the microcomputer, a menu picture plane for function selection is displayed on the monitor by a signal generating circuit. On the basis of the picture plane, by remote controller selection or the like, the user can set a helper killer function, for suppressing helper signals intended to reinforce vertical resolution, to be on or off as required.