Abstract: In an adaptive differential PCM (ADPCM) system transmitter, three quantizers provide, respectively, 3, 4, and 5-bit quantization at the signal sampling rate. Each quantizer produces, in response to an input signal sample, a coded signal I(n) in the form of a bit sequence the number of bits in the coded signal from each quantizer being different. The number of bits comprising the coded signal is proportional to the bit rate. The bit rate can thus be altered by switching the codec output to selected ones of the adaptive quantizers. To eliminate quantizing distortion during bit rate transitions, one adaptive quantizer is caused to operate in the dominant mode, to receive the input signal sample and produce the coded signal I(n). At the same time, the other adaptive quantizers operate in a secondary mode to update their step-size .DELTA.(n) on the basis of the quantized signal produced by the dominant mode quantizer.

Abstract: The free radical hydrobromination reaction of an olefinic compound is initiated photochemically by irradiating a mixture of hydrogen bromide and the olefinic compound with coherent light having a wavelength in the range from about 335 to about 500 nm.

Abstract: The rate of evaporation of material from a laser-heated target is enhanced by coating the target with a layer of condensed substantially inert gas.