Patent
A programmable electronic filter
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TLDR
In this paper, the authors propose a filter with variable resistance components (R) controllable by variation of control current, where each resistance component comprises a multiplicity of series connected stages, each stage including a diode (D).Abstract:
A filter including one or more variable resistance components ('R') controllable by variation of control current. Each resistance component comprises a multiplicity of series connected stages, each stage (Fig. 3) including a diode (D). The diode (16, 18,... 20) of successive stages are arranged in alternate sense. The resistance component may include a buffering transistor (14) at its input. The resistance may be made arbitrarily large merely by the design choice of including a sufficiently large number of stages. The filter may include a plurality of variable resistance components. For frequency scaling, these components would be connected in parallel to a common source of control current. Alternatively, for variation of shaping characteristics, they may be controlled independently.read more
Citations
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References
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