The Magnus phase shifter

[Rory McDonald]

Jergen:Do you know if this is true as well for the CS-50/60?
Just curious...
Rory McDonald

-----Original Message-----
From: Haible Juergen [mailto:Juergen.Haible at nbgm.siemens.de]
Sent: Friday, September 22, 2000 9:31 AM
To: Don Tillman
Cc: DIY
Subject: RE: The Magnus phase shifter


	>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.