Abstract: A logarithmic I.F. amplifier having a common input terminal for receiving input signals with the method of construction including a pair of channels connected in a parallel configuration, the first channel being non-attenuated for receiving an input signal at full signal strength while the second channel is attenuated for substantially reducing the power level of the input signal, the construction resulting in saturation of a plurality of successive amplifying stages of the non-attenuated channel with increasing input signal strength prior to the delayed saturation of a plurality of duplicate amplifying stages of the attenuated channel, the attenuated channel continuing to provide compressed output signal data after the saturation of the amplifying stages of the non-attenuated channel, the sum of the output signal data from the pair of channels being effected on a summation line for providing an extended dynamic range of the logarithmic I.F. amplifier.