[sdiy] VCO compensation suggestion

[patchell]

    I was trying to get away from passive comensation...this would not be any
different than using a Tempco resistor, although, it would be a lot less
expensive.  I wanted to use the transistors that were doing the expo function
themselves as the temp sensors...this way, there would be no doubt that
everything was tracking right on.

    As far as being more complicated...well, maybe.  Although, the actual real
estate used on the board by the compensation electronics is only about 20%.

    One thing for sure though, I don't think I want to build another one on
perf board. ;^)

Ian Fritz wrote:

> Hi all --
>
> This post refers to a circuit shown in the following article
>
> http://www.engr.uconn.edu/~keramat/EE300/pwdfiles/ota.pdf
>
> as Fig. 2 (g).
>
> It consists of two cascaded OTAs.  It seems to me that if the first OTA is
> hooked up to include the linearizing diodes and the second is not, then the
> composite voltage gain is proportional to temperature.  If this is correct,
> then there is no need to build any additional circuitry such as the bandgap
> reference recently discussed.
>
> Let me know what you think!
>
>    Ian

--
 -Jim
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