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A true logarithmic response amplifier based on a parallel signal path topology is described in this paper. The parallel topology provides wide bandwidth response compared to conventional series cascaded topologies. The amplifier has been fabricated in a 35 GHz bipolar RF process, and measurements show that it exhibits 50 dB logarithmic voltage range with a 4 GHz bandwidth. An example application is provided, describing the generation of single-sideband data streams for fiber-optic networks. Simulation shows that inclusion of the logarithmic amplifier in the signal processing path improves sideband cancellation by over 15 dB