(under subclass 249) Subject matter in which the companding is instantaneous.
(1) Note. There are two types of syllabic adaptative
modulators namely, the analog syllabic adaptative modulators and the digital syllabic adaptative modulators depending on whether the gain control signal of the amplifier is derived from the input analog input signal or from the coded digital output signal. The gain control signal may be derived from the input analog signal using a simple envelope detector. Similarly, the gain control signal may be derived from the digital output by means of a syllabic filter. Such syllabic adaptative modulators will provide a continuous adaptation of the gain of the amplifier so as to vary the amplitude of the steps of the integrator accordingly. The instantaneous adaptation or companding is derived from the digital output signal on a short time basis.
