| 摘要 |
An amplifier stage for a logarithmic amplifier having a plurality of such stages connected in cascade. Each stage comprises a linear amplifier and a differential amplifier having a common load resistance, a common input terminal and a common output terminal at one end of the load resistance; these two terminals are also the input and output terminals of the stage. The linear amplifier delivers an output which is a linear function of its input over the entire range of permissible input values. The differential amplifier delivers an output which is a linear function of its input for input values below a predetermined limit, and delivers a constant output for input values above this limit. The output of the stage is the sum of the output from the linear amplifier and the output from the differential amplifier. Below the predetermined limit the output of the stage is thus the sum of two linear outputs; above this limit it is the sum of a linear output and a constant output. The gain of the stage is therefore constant below the limit, but falls off above the limit.
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