The Magnus phase shifter

[Martin Czech]

You can hide the discharge time with a single current source,
dual integrator approach. While one integrator discharges
the other charges and so on.

Just an idea.

m.c.

:::X-Envelope-Sender-Is: Juergen.Haible at nbgm.siemens.de (at relayer 
gecko.sbs.de)
:::From: Haible Juergen <Juergen.Haible at nbgm.siemens.de>
:::To: Don Tillman <don at till.com>
:::Cc: DIY <synth-diy at node12b53.a2000.nl>
:::Subject: RE: The Magnus phase shifter
:::Date: Fri, 22 Sep 2000 18:31:07 +0200
:::
:::	>It is now. 
:::
:::Thank you ! 
:::
:::	>  The VCO uses a charge pump (!!!) to discharge the cap without any
:::	>  high frequency linearity issues.
:::
:::Yes, charge pump. The CS-80 does this as well.
:::I wonder how they fill the rather large gap of the saw reset time when
:::a triangle is created. 
:::
:::For those who are not familiar with that kind of VCO:
:::Normally the scale error that is caused by the reset time of the saw wave
:::must be compensated in the expo converter, and there ar a lot of
:::stategies to keep that time small. The Chroma and CS-80 VCOs
:::don't go for an ultra fast reset time, but the VCO concept includes a 
:::perfect compensation. At least that's who I understand it.
:::I've seen a discrete design of this from R.A.Pease, and I think National
:::still have such a chip as well.
:::
:::I wonder if ARP's HFT compensation in the Odyssey is a predecessor
:::of this as well. There's a certain amount of charge used for compensation
:::rather than a continuous current as well. (If memory serves. Was some time
:::since I last looked at Odyssey schemos.)
:::
:::JH.