[sdiy] TZ triangle core

[lanterma at ece.gatech.edu]

Now is the time on Sprockets when an actual schematic would work  
wonders, assuming David is ready to show his cards.

- Aaron

Sent from my iPhone

On Mar 2, 2011, at 6:00 PM, "Ian Fritz" <ijfritz at comcast.net> wrote:

> Sorry, I can't understand this at all.  You seem to be giving a lot  
> of peripheral information without saying what the circuit is.
>
> Ian
>
>
> At 03:19 PM 3/2/2011, David G. Dixon wrote:
>> > I don't get it. Where does the modulation go, ie where is the
>> > multiplier?
>>
>> In the loop.  The Linear FM circuit is a balanced modulator (four- 
>> quadrant
>> multiplier) made up of two linearized 2164s.  The (optionally  
>> inverted)
>> triangle is driving two comparators with opposite inputs (each  
>> limited with
>> separate zener circuits), and each zener-limited comparator output is
>> dropped across a resistor and fed into one side of the modulator.   
>> By using
>> two comparators (LM319), I didn't have to invert anything by  
>> converting
>> currents to voltages, which is slow.  Only currents are going  
>> around the
>> loop at virtual ground.  Also, with the balanced modulator, I  
>> easily get
>> voltage-controlled time reversal (a la the "Zeroscillator").  Also,  
>> because
>> one input of each comparator is grounded, I obtain variable sync  
>> simply by
>> spiking it.
>
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