| 摘要 |
A syllabic compander uses logarithmic chains in both the compressor and expander. The logarithmic chains are each constructed of a logarithmic amplifier, a scaler, and an antilogarithmic amplifier or their equivalents. The output of a logarithmic chain is equal to the input raised to a power determined by the scale factor of the scaler. A logarithmic chain is used with a multiplier and an average value circuit to implement equations of the form uo=KuiUa where ui is the input to the compressor or expander, uo is the output of the compressor or expander, U is the rms (or pseudo-rms) value of ui or uo averaged over the time of one syllable, K is a constant, and a is the scale factor which is a function of the compression or expansion rate. Since the scale factor a may be easily adjusted, the compander permits flexibility in changing the compression and expansion rates. |
