Abstract: A heating device for water beds comprises a plurality of electrical resistance conductors arranged between a bed frame and a safety foil, means for controlling the conductors in dependence on the desired temperature of a water core locatable under the safety foil, a plurality of ceramic plates arranged so that the conductors are burnt-in the ceramic plates, a bending resistant metal plate having a lower side, the ceramic plates being glued to the lower side of the metal plate by an adhesive having high thermal conductivity, and a base plate having poor thermal conductivity and placeable on the bed frame, the metal plate being arranged on the base plate in a form-locking manner with an air gap for the ceramic plates.

Abstract: System for the vocoder transmission of speech signal with reduced bandwidth. The speech signal is split into a low-frequency part and a high-frequency part. The high-frequency part is subdivided into a number of sub-bands and for each sub-band a control signal with reduced bandwidth is transmitted. A control signal is representative for the ratio between the energy in the sub-band of the speech signal and the energy in the corresponding sub-band of a reference signal with high-frequency components, which is produced from the low-frequency part of the speech signal.