| 摘要 |
A logarithmic gain circuit comprising: (a) a resistive attenuator including i. an input conductor and an output conductor, ii. a plurality of series resistive elements connected in series between the input conductor and the output conductor, and iii. a plurality of parallel resistive elements each having a first terminal connected to a successive junction, respectively, between the various series resistive elements; (b) a plurality of switching elements operative to controllably electrically couple the parallel resistive elements, respectively, between the successive junctions and a first reference voltage conductor, each switching element having a control terminal; and (c) an analog control circuit producing a plurality of successive control signals on the control terminals of successive switching elements, respectively, in response to linear changing of an analog gain control signal from a first value to a second value, a magnitude of each control signal gradually increasing and then leveling off at a predetermined value.
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