In this paper a short theoretical overview of differential quantizer and its
implementations is given. Afterward, the effect of the order of prediction in
differential quantizer and the effect of the difference in order of predictor
in the input and output of differential quantizer is analyzed. Then it was
proceeded with the examination of the robustness of the differential
quantizer in the case in which a noise signal is brought to the input of the
differential quantizer, instead of the clean speech signal. The analysis was
conducted with a uniform distribution, as well as the noise with the gaussian
distribution, and the obtained results were adequately commented on. Also,
experimentally a limit was set which refers to the intensity of the noise and
still enable results which are better that a regular uniform quantizer. The
whole analysis is done by using the fixed number of bits in quantization,
i.e. 12-bit quantizer is used in all the implementations of differential
quantizer. In the conclusion of this paper there is a discussion about the
possibility of implementing a differential quantizer which will be able to
recognize which noise attacks the system, and in addition to that, in what
form it adapts its coefficients so that it at any moment acquires the optimal
signal to noise ratio.