Abstract: A speech compressor utilizing Trellis Encoding and Linear Prediction (TELP). A TELP speech compressor provides improved signal generation and search technique for a code-excited linear prediction (CELP) speech encoder. TELP is a frame oriented coding that breaks the quantized speech signals into frames of prescribed length N and each frame into subframes of prescribed length L, which are processed as dependent units utilizing an analysis-by-synthesis approach. The approach is based on constructing the best mean square linear predicting filter and searching the best exciting sequence for the filter in order to produce synthesized speech. A trellis encoder is used instead of a stochastic code book. The Q-ary analysis of a given subframe and previous excitations is proposed for a fast vector search in an adaptive code book. It simplifies the implementation of digital speech compression.

Abstract: A cold-setting mixture for the production of casting moulds and cores comprises the following components, in parts by weight:Refractory filler -- 100Binder, viz., novolac phenol-formaldehyde resin -- 0.5 to 5.0Hardener, viz., polyisocyanate -- 0.005 to 1.0Organic solvent -- 0.5 to 5.0Hardening catalyst -- 0.0025 to 5.0The catalyst employed in this mixture is a composition which comprises silicates and aluminates of alkaline-earth metals, cements, slags of ferrochrome manufacturing process, nepheline slurry and basic salts, e.g. sodium carbonate.The catalyst due to easy proportioning thereof, makes it possible to reduce the cost of the mixture, reduce the amount of polyisocyanate required, and simplify the preparation of this mixture.The proposed cold-setting mixture has enhanced strength properties and improves the quality of casting mould and cores being made therefrom.