RE(2): RE(2): matched expo source / sink idea

[Osamu Hoshuyama]

Hello JH,

> Date:    Thu, 24 Feb 2000 13:55:44 +0100
> From:    Haible Juergen <Juergen.Haible at nbgm.siemens.de>
> Dear Osamu,
> 
> Thanks for sharing this.
> Placing the "npn diode" after the pnp emitter follower looks good !
> 
> I'm still puzzled how to drive a diode bridge with this configuration,
> though.
> Wouldn't driving a diode bridge mean the voltage of the source output
> has to be higher than the voltage of the sink output ?
> 
> JH.

I'm sorry for insufficient explanation.
Two additional current mirrors are needed.

The current-driven diode bridge (CDDB) can be considered as a floating
resistor bridge, which is more flexible than the voltage-driven diode
bridge in MS50 VCF.  We don't have to worry about the influence of
driver circuit of the CDDB.  For example, we can easily replace
resistors of a bridged-T filter with a CDDB.

- -- ---- ----------- --- --- - ----- -- --- --- - - ------ - - - --
 Osamu HOSHUYAMA          Digital Signal Processing Technology Group
                    C&C Media Research Laboratories, NEC Corporation
               Email: houshu at ccm.CL.nec.co.jp,  Fax: +81-44-856-2232
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