The set frequency distortions between cascades distribute so that to receive the smallest cost and overall dimensions of the amplifier. The greatest frequency distortions give transformer intensifying cascades. Therefore at the lower frequency in the transformer cascade the coefficient of distortions is century.3 times above, than in the ordinary resistor cascade. With a low frequency of range it is possible to apply a low-frequency to reduction of the sizes of transitional condensers. At the top boundary frequency of range of sound frequencies frequency distortions can be shown considerably only in transformer cascades which can be reduced a choice of parameters of the transformer (reduction of inductance of dispersion and mezhvitkovy capacity). In amplifiers for receiving perhaps bigger strengthening it is necessary to enter high-frequency correction into each cascade.
The coefficient of noise of the multicascade amplifier generally is defined by noise of an entrance chain and the first cascade. For reduction of noise at the exit of the amplifier it is necessary to have the maximum coefficient of strengthening on power, i.e. the amplifier has to be coordinated on an entrance and an exit.
where Kr and Kp1 — coefficients of transfer and strengthening on the power of the input device and the first cascade of the amplifier. The coefficient of noise of an entrance chain Kshvkh is considered for amplifiers if as an entrance chain the transformer or a feeder is used. In this case Kshvkh=1/Krvkh.
where kvkh=zvkh / (Zg + Zvkh) – coefficient of transfer of an entrance chain. If to express coefficient of strengthening of separate cascades in logarithmic units, the general coefficient of strengthening of the multicascade amplifier will be equal to the sum of coefficients