tri lfo with 90deg lag?

[Haible Juergen]

	>Wanting to have a triangle LFO, with a second one at the
	>same frequency and 90deg out of phase. Over a .02 to 2KHz range.
	>
	>I'm thinking of synthesing these from a saw wave at twice the
frequency,
	>with a 4 cycle switching arrangement. But, there must be a simpler
way!
	>What do people think?
	>I dont want to use a counter with D to A because at low freq the
stepping 
	>would be intrusive.
	>
	>paul perry melbourne australia 

Take a look at http://www.synthfool.com/diy/hjqvco.gif

Omit the tri->sine shapers, and there's only one TL074 and one LM13700 left.
If you don't need voltage control, omit the OTAs as well.
(Use a stereo pot and change the circuit slightly for inverting opamp
integrators.)

JH.