Siemens Aktiengesellschaft

Ulrich Totzek

Matthias Schoebinger

Fred Matthiesen

Bernd Zehner

In DPCM coders, respective estimated values are subtracted from digitized picture element signals and the estimated errors are employed for signal transmission following quantization and coding. Each estimated error is quantized with a fictitious, positive operational sign in a first programmable logic arrangement and, parallel thereto, is quantized with a fictitious negative operational sign in a second programmable logic arrangement. Of these two quantizing results, the correct result is selected via a multiplexer controlled by the actual operational sign of the estimated error.

Arrangement for DPCM coding of television signals with fast signal

In a DPCM coder respective estimated values are subtracted from digitized picture element signals and estimated errors are used for signal transmission after quantization and coding. Each estimated value is derived from a reconstructed picture element signal formed in an adder. Separate, simultaneous subtractions of the signal taken at the output of the adder, as well as of the positive and negative adder limit values, from the respective picture element signal at the input thereby occur, whereby an overflow recognition device and a multiplexer provide that only the difference from the three differences formed up to this point are taken into consideration for quantization on the basis of the actual addition result, including no overflow, positive overflow and negative overflow.

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Munich, Germany

Ulrich Totzek