Path: news.eternal-september.org!eternal-september.org!feeder3.eternal-september.org!usenet.blueworldhosting.com!diablo1.usenet.blueworldhosting.com!nnrp.usenet.blueworldhosting.com!.POSTED!not-for-mail From: "Edward Rawde" Newsgroups: sci.electronics.design Subject: Re: Low distortion sinewave oscillator without big capacitor. Date: Tue, 8 Apr 2025 21:04:25 -0400 Organization: BWH Usenet Archive (https://usenet.blueworldhosting.com) Lines: 328 Message-ID: References: <8099vjhs62eofoioejtlssoa19ifjrdvcg@4ax.com> Injection-Date: Wed, 9 Apr 2025 01:04:27 -0000 (UTC) Injection-Info: nnrp.usenet.blueworldhosting.com; logging-data="84876"; mail-complaints-to="usenet@blueworldhosting.com" Cancel-Lock: sha1:szySyeZfc+s0O+VHnV4SlErdKms= sha256:B4gUpdwbQZ6fsWssR8sX+f6u62/dQgjVLwWE2JNf53Y= sha1:FIpyjaXteFG9AsXTUORwgqeJpFM= sha256:qMydx+ql7O0zEjQjrGDgbcZ9u8Bvdbd69v0PSJyjx+s= X-Newsreader: Microsoft Outlook Express 6.00.2900.5931 X-RFC2646: Format=Flowed; Original X-Priority: 3 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 X-MSMail-Priority: Normal "JM" wrote in message news:vhabvj1uo56ikdhu8if219rvtfal6lijee@4ax.com... > On Tue, 8 Apr 2025 14:41:44 -0400, "Edward Rawde" > wrote: > >>"JM" wrote in message news:8099vjhs62eofoioejtlssoa19ifjrdvcg@4ax.com... >>> On Mon, 7 Apr 2025 22:46:13 -0400, "Edward Rawde" >>> wrote: >>> >>>>"Edward Rawde" wrote in message news:vsso97$1imi$1@nnrp.usenet.blueworldhosting.com... >>>>> "JM" wrote in message news:tcl2vjp49q4ga21itrpnmr4u3ts06vqffd@4ax.com... >>>>>> On Fri, 4 Apr 2025 23:55:11 -0400, "Edward Rawde" >>>>>> wrote: >>>>>> >>>>>>>"JM" wrote in message news:uop0vjp3d13t441ujfboi5aeeg08anm1je@4ax.com... >>>>>>>> On Fri, 4 Apr 2025 16:29:27 -0400, "Edward Rawde" >>>>>>>> wrote: >>>>>>>> >>>>>>>>>"JM" wrote in message news:add0vjdh2gcma0n9pfunq76n04cfbkhtnj@4ax.com... >>>>>>>>>> On Fri, 4 Apr 2025 14:25:29 -0400, "Edward Rawde" >>>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>>>"Bill Sloman" 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" >>>>>>>>>>>>> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>> "JM" wrote in message news:qq8tujlpciqc2jrd0ibljmjr9pd37ip6hi@4ax.com... >>>>>>>>>>>>>>> On Sun, 30 Mar 2025 14:54:56 -0400, "Edward Rawde" >>>>>>>>>>>>>>> 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. >>>>>>>>>>>>.... >>>> >>>>Here's an almost fully practical circuit except for the current sources and sinks. >>>> >>> >>> I reversed the polarity of the control feedback and applied it to the >>> inverting input of the first oscilllator stage, removed some >>> redundant capacitors, and added some filtering to the gain control >>> signal. Also altered some gain values to improve the dynamics (but >>> that still has to be addressed). >>> >>> Most real world designs would use a sample and hold circuit to sample >>> the output at it's maximum point and use that to control the feedback, >>> similar to the topology I think I posted a while ago. It might be >>> worthwhile looking at that. >>> >>> >>Thanks. That has the lowest distortion I've seen in a simulation so far. >> >>I can't find the sample/hold circuit you mentioned, would you mind reposting it? >> >>Thank you for your help with this. It is much appreciated. >> >> > Is the sample/hold circuit the one below? After much digging I found it in a very interesting thread started by Bill Sloman on 5th February 2025 "The low distortion oscillator problem". I can't get it to simulate in 24.1.5 something to do with unknown parameter in table{-2m,0,2m,1} Version 4 SHEET 1 3020 1316 WIRE 208 -192 -160 -192 WIRE 928 -192 288 -192 WIRE -160 -80 -160 -192 WIRE 208 -80 -160 -80 WIRE 528 -80 288 -80 WIRE -160 32 -160 -80 WIRE -48 32 -160 32 WIRE 96 32 32 32 WIRE 208 32 96 32 WIRE 336 32 288 32 WIRE 384 32 336 32 WIRE 528 32 528 -80 WIRE 528 32 448 32 WIRE 608 32 528 32 WIRE 736 32 688 32 WIRE 784 32 736 32 WIRE 928 32 928 -192 WIRE 928 32 848 32 WIRE -160 144 -160 32 WIRE -48 144 -160 144 WIRE 336 144 336 32 WIRE 384 144 336 144 WIRE 736 144 736 32 WIRE 784 144 736 144 WIRE -336 160 -336 144 WIRE -336 160 -400 160 WIRE 96 160 96 32 WIRE 96 160 16 160 WIRE 528 160 528 32 WIRE 528 160 448 160 WIRE 928 160 928 32 WIRE 928 160 848 160 WIRE 1216 160 928 160 WIRE -400 176 -400 160 WIRE -336 176 -336 160 WIRE -48 176 -160 176 WIRE 384 176 336 176 WIRE 784 176 736 176 WIRE 336 208 336 176 WIRE 736 208 736 176 WIRE -160 288 -160 176 WIRE -64 288 -160 288 WIRE 528 288 528 160 WIRE 528 288 16 288 WIRE 1264 288 528 288 WIRE -160 368 -160 288 WIRE 272 400 192 400 WIRE 416 400 336 400 WIRE 928 448 928 160 WIRE 928 448 848 448 WIRE 192 496 192 400 WIRE 272 496 192 496 WIRE 416 496 416 400 WIRE 416 496 336 496 WIRE 544 496 496 496 WIRE 672 496 624 496 WIRE 1040 512 848 512 WIRE 1120 512 1040 512 WIRE 1216 512 1120 512 WIRE 1040 560 1040 512 WIRE 1216 560 1216 512 WIRE 1120 576 1120 512 WIRE 1264 576 1264 288 WIRE 192 592 192 496 WIRE 240 592 192 592 WIRE 320 592 304 592 WIRE 416 592 416 496 WIRE 416 592 400 592 WIRE -208 640 -240 640 WIRE -160 640 -160 448 WIRE -160 640 -208 640 WIRE 1216 656 1216 640 WIRE 1264 656 1264 624 WIRE 1264 656 1216 656 WIRE 192 672 192 592 WIRE -240 688 -240 640 WIRE -160 688 -160 640 WIRE 1040 688 1040 640 WIRE 1120 688 1120 640 WIRE 1216 688 1216 656 WIRE 416 704 416 592 WIRE 416 704 336 704 WIRE 496 704 496 496 WIRE 496 704 416 704 WIRE 544 704 496 704 WIRE 672 704 624 704 WIRE 928 704 736 704 WIRE -16 720 -48 720 WIRE 32 720 -16 720 WIRE 192 720 192 672 WIRE 192 720 112 720 WIRE 272 720 192 720 WIRE 416 736 336 736 WIRE -16 768 -16 720 WIRE 416 768 416 736 WIRE 928 768 928 704 WIRE -240 816 -240 768 WIRE -208 816 -240 816 WIRE -160 816 -160 768 WIRE -160 816 -208 816 WIRE -160 864 -160 816 WIRE -16 864 -16 832 FLAG 336 208 0 FLAG 736 208 0 FLAG -400 176 0 FLAG -336 64 vcc FLAG -336 256 vee FLAG 1216 160 vout FLAG 192 672 vx ========== REMAINDER OF ARTICLE TRUNCATED ==========