Path: ...!news.misty.com!weretis.net!feeder9.news.weretis.net!usenet.blueworldhosting.com!diablo1.usenet.blueworldhosting.com!nnrp.usenet.blueworldhosting.com!.POSTED!not-for-mail
From: "Edward Rawde" <invalid@invalid.invalid>
Newsgroups: sci.electronics.design
Subject: Re: Low distortion sinewave oscillator without big capacitor.
Date: Fri, 4 Apr 2025 16:29:27 -0400
Organization: BWH Usenet Archive (https://usenet.blueworldhosting.com)
Lines: 57
Message-ID: <vspff8$a02$1@nnrp.usenet.blueworldhosting.com>
References: <vsc420$2ic$1@nnrp.usenet.blueworldhosting.com> <qq8tujlpciqc2jrd0ibljmjr9pd37ip6hi@4ax.com> <vsn5df$o10$1@nnrp.usenet.blueworldhosting.com> <vh9uujhi6chpejn8nfhdh67afc23kfqq32@4ax.com> <vsnufh$2ou7j$1@dont-email.me> <vsp86r$174f$1@nnrp.usenet.blueworldhosting.com> <add0vjdh2gcma0n9pfunq76n04cfbkhtnj@4ax.com>
Injection-Date: Fri, 4 Apr 2025 20:29:28 -0000 (UTC)
Injection-Info: nnrp.usenet.blueworldhosting.com;
	logging-data="10242"; mail-complaints-to="usenet@blueworldhosting.com"
Cancel-Lock: sha1:RZvV44dd546wykQPKT/49dc/B5E= sha256:1atUtTFKVL42kt0wvZkIEULSErsau5WvYbK6ANGynf0=
	sha1:1SdK4cDWkcOXtQ9rdpMYVAKedj4= sha256:IthSNx4vRiFXOkAVKQNjBDdrPCm8OaDMuMqvcwKTVCo=
X-RFC2646: Format=Flowed; Original
X-Priority: 3
X-MSMail-Priority: Normal
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157
X-Newsreader: Microsoft Outlook Express 6.00.2900.5931
Bytes: 3807

"JM" <sunaecoNoChoppedPork@gmail.com> wrote in message news:add0vjdh2gcma0n9pfunq76n04cfbkhtnj@4ax.com...
> On Fri, 4 Apr 2025 14:25:29 -0400, "Edward Rawde"
> <invalid@invalid.invalid> wrote:
>
>>"Bill Sloman" <bill.sloman@ieee.org> wrote in message news:vsnufh$2ou7j$1@dont-email.me...
>>> On 4/04/2025 11:33 am, JM wrote:
>>>> On Thu, 3 Apr 2025 19:25:33 -0400, "Edward Rawde"
>>>> <invalid@invalid.invalid> wrote:
>>>>
>>>>> "JM" <sunaecoNoChoppedPork@gmail.com> wrote in message news:qq8tujlpciqc2jrd0ibljmjr9pd37ip6hi@4ax.com...
>>>>>> On Sun, 30 Mar 2025 14:54:56 -0400, "Edward Rawde"
>>>>>> <invalid@invalid.invalid> wrote:
>>>>>>
>>>>>>> Not long ago JM posted a 1KHz sinewave oscillator with very low distortion.
>>>>>>> It used a 470uF non polarized capacitor which in practice would probably be made from two 1000uF capacitors.
>>>>>>> There's nothing wrong with that but I wanted to see whether I could make a working circuit without needing such a large
>>>>>>> capacitor.
>>>
>>>> You will need to adjust the feedback to suit.  Start with a -5 or -6
>>>> gain block after the integrator and adjust it's gain until the startup
>>>> is clean (no saturation).
>>>
>>> Here's my version of John May's variation.
>>>
>>...
>>
>>Yes, that works but only 120dB down at 4KHz.
>>I put the damping resistor back to 47k since I don't care what happens during the first few seonds as long as it happens.
>>If it's necessary to wait one minute for the purest tone, that's fine with me.
>>
>>>
>>> Linewraps are going to be a problem - delete all "\n" from the last few lines
>>
>>You don't want to remove \n just remove the wraps.
>>
>>BCM61B does not have two independent transistors.
>>
>>So you probably want BCM847BS which has two independent matched transistors and a very low price at digikey, so may as well use 
>>two
>>of them as shown below.
>>
>>I took the model from
>>https://github.com/peteut/spice-models/blob/master/nxp/complex_discretes/complex_discretes.txt
>>
>>It should only be necessary to unwrap the last line of the following.
>>Don't remove \n just remove the wraps, you may need to use a horizontal scroll bar.
>>
>>Version 4.1
>
>
> Best to just offset the integrator output so the amplitude is brought
> under control sooner.
>

Wow. That has much lower distortion too.