Block diagram of CS-80 VCO chip online

[Magnus Danielson]

From: "Bjorn Julin" <bnillson at hotmail.com>
Subject: Re: Block diagram of CS-80 VCO chip online
Date: Sat, 07 Oct 2000 20:50:43 GMT

Hi!

> >There is a fascinating history of VCOs in "Analog Circuit Design:
> >Art, Science, and Personalities"(ed. Jim Williams), where Bob Pease >who 
> >designed the LM311 shows its history.. right back to a circuit >from 1967, 
> >from SWEDEN, of all places! What a coincidence BJ! (Maybe >an uncle?)
> 
> Well, well, i dont know how many times i have posted just
> this you are talking about here to this list.
> 
> The first time some yeras ago it did go to the list and so
> the second time, but not the third time and not the forth
> time, quite frustrating!
> 
> >Incidentally, the 'magic' in this ckt (consisting of an opamp and a >UJT) 
> >was that on each output pulse, a precise amount of charge was >fed back to 
> >discharge the integrating capacitor.
> >Pease points out that the RC1451 VCO (1970) was the first IC VFO, but >was 
> >timer based like the 555. And, consequently, not very linear or >temp 
> >stable. Pease is rather disparaging in his comments on the >unknown hero 
> >from Sweden, saying "apparently the Swedish engineers >had stumbled onto 
> >this crude but functional circuit". Well, I don't >know whether it was 
> >'stumbled' on or not.
> 
> The first paper i have read was a very old paper from National
> not written by Bob, the second paper about this was from swedish
> source (un known) and there was a short story that they didnt "stumbled" on 
> to it, as far as i can recall it was actually
> used in some product for the company where one of the
> engineers worked. But im not 100% sure if i recall it right!
> 
> Someone who might have these papers might be Magnus D?

<In a deep voice>
Sir, you rang.
</In a deep voice>

Hum, no, I am sad to report that I don't really have much of National
databooks, so I don't have any app-notes describing this.

I must say that this story intreagues me, I was just woundering if the
father to one of my colleagues would possibly know anything about
this. He is one of those analog monsters you know ;)

> Paul, i would be interested to read that story from your book,
> is it to much text/work/hassle and stress to scan?

I would naturally be interested to read more about this too ;)

Cheers,
Magnus