Re: Sine generator IC solution?

From: Ben Bradley (ben_nospam_bradley_at_frontiernet.net)
Date: 01/31/05 

Date: Mon, 31 Jan 2005 00:29:59 GMT

On Sun, 30 Jan 2005 16:31:35 GMT, Fred Bloggs <nospam@nospam.com>
wrote:

>
>
>Spehro Pefhany wrote:
>
>> An op-amp (or a few discrete transistors if you ignore the "IC
>> solution" part of the OP's question) and a handful of passives and a
>> nonlinear element of some kind (lamp, thermistor etc.) can be used to
>> make a Wien bridge oscillator, probably the most easily adjustable
>> sine-wave oscillator. But the specs might push the solution somewhere
>> else. If you google on "Wein bridge" and "Wein bridge" (the latter
>> has 3 times as many hits, though some may lead you to bridges over the
>> Danube) you should get some good ideas.
>>
>
>You're not going to do much in the way of a 10:1 tuning range in Wien
>bridge- fussy little high Q and amplitude unstable thing that it is.

   Didn't the original HP oscillator do just exactly that?

>These days the most practical and high performance approach, at these
>frequencies, would be to generate a variable frequency square wave at
>fundamental and 100x fundamental which are then processed by cheap
>switching tracking filter.

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