AbstractAt present, analog circuits are used widely for syllabic companding which effectively improves the quality of speech communication. The digitalization of the syllabic companding circuit promises several advantages, namely, the possibility of adapting filter coefficients to the condition of the radio communication system, the elimination of adjustments, the possibility of large‐scale integration, etc. The present paper considers such a new approach, a digital signal processing syllabic compander. The realization method is described and the results of both theoretical and computer aided investigations concerning the characteristics of the compander are presented. First, the construction of the digital signal processing compander is shown. Then detailed theoretical investigations are given on the influence of the distortion which is a specific problem of the digital realization. The results obtained agree well with those of the computer‐aided analysis. According to the investigations presented it has become clear that the sampling frequency should exceed 24 kHz in order to attain a signal‐to‐distortion ratio of above 40 dB in the voice frequency band for a separate compressor and an expander. However, if the compressor and expander are connected in a system, then a distortion cancellation effect arises which allows a considerable reduction of the sampling frequency. The transient response has also been investigated, and the same characteristics have been obtained as in the case of analog companders.