Block diagram of CS-80 VCO chip online

[Bjorn Julin]

>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?

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

Reg
BJ
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