Re: The not-all-that-low distortion sine wave oscillator in a faster simulating version

"Bill Sloman" <bill.sloman@ieee.org> wrote in message news:vjtgnp$24ubg$1@dont-email.me...

I've been playing with the circuit, and have got rid of one op amp, which made the simulation run much faster, but didn't help the
distortion performance.
>
Swapping the LT1115 for the LME49710 speeded up the simulation a bit more, but didn't make any difference to the distortion
either. A few of the ferrite beads have gone too.
>

I got a simulation speed of about 30us/s so I didn't wait the nearly 4 days it would take to complete.
I did an FFT on the first few cycles and it does look 100dB down up to 1.5MHz.

But what's the point when the circuit below is comfortably 120dB down in simulation using less than half the number of components?

It requires only a single rail and if 60dB will meet your needs then a single 9V battery is fine.

All the components are doing what I want them to do and I know what they all do.

To attempt do any better in simulation I'd replace D1 with a precision rectifier at 0 and 180 degrees and maybe 90 and 270 too.

If building this for real then ten turn trimmers would be used for:
R14 2.2k
R3 68 ohm
R16 100k
And I'd also want R19 or part of it variable.

I wish LTSpice had a "Do you want to fix apparent line wraps Y/N". That shouldn't be hard.

Also is there any way in LTSpice to find a component?
What I mean is let's say you have a schematic like Bill's schematic and you know that R17 is there somewhere but you don't know
where.

Version 4
SHEET 1 2196 932
WIRE 864 -784 704 -784
WIRE 944 -784 944 -816
WIRE 768 -720 768 -736
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WIRE 592 -416 480 -416
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WIRE 256 -400 256 -544
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WIRE 1136 -288 1008 -288
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WIRE -112 -256 -144 -256
WIRE 16 -240 16 -352
WIRE 16 -240 -48 -240
WIRE 64 -240 16 -240
WIRE 96 -240 64 -240
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WIRE 1136 -192 1024 -192
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WIRE -192 -176 -256 -176
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FLAG 496 -16 V+
FLAG 928 0 V+
FLAG 208 -176 gate
FLAG 128 16 drn
FLAG 1520 176 0
FLAG 1456 16 output
FLAG -416 -32 0
FLAG 384 -352 0
FLAG 496 80 0
FLAG 928 96 0
FLAG -416 -304 V+
FLAG 448 -384 half
FLAG 432 48 half
FLAG 864 64 half
FLAG -80 -176 0
FLAG -80 -304 V+
FLAG 64 -240 half
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FLAG -192 -512 V+
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WINDOW 3 -9 -3 VRight 2
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WINDOW 123 0 0 Left 0
WINDOW 39 10 135 Left 2
WINDOW 0 10 0 Left 2
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SYMBOL schottky 1056 -432 R90
WINDOW 3 32 32 VTop 2
WINDOW 0 0 32 VBottom 2
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SYMATTR InstName D1
SYMATTR Description Diode
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WINDOW 0 -4 57 VBottom 2
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WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
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SYMATTR Value 8.2k
SYMBOL res 1104 -112 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R16
SYMATTR Value 47k
SYMBOL OpAmps\LT1058 -80 -304 R0
SYMATTR InstName U5
SYMBOL OpAmps\LT1058 384 -464 M0
SYMATTR InstName U6
SYMBOL OpAmps\LT1678 928 48 R0
SYMATTR InstName U3
SYMBOL OpAmps\LT1678 496 32 R0
SYMATTR InstName U4
SYMBOL OpAmps\LT1058 768 -752 M0
WINDOW 0 -79 26 Left 2
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SYMATTR Value 100k
SYMBOL res 928 -640 R0
SYMATTR InstName R20
SYMATTR Value 120k
SYMBOL cap 1040 -544 M180
WINDOW 0 24 56 Left 2
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SYMATTR Value 10n
SYMATTR SpiceLine V=50 Irms=291m Rser=0.34258 Lser=0 mfg="KEMET" pn="C0805F103K5RAC" type="X7R"
TEXT -496 136 Left 2 !.tran 0 30 0 1u uic
TEXT -496 88 Left 2 !.options plotwinsize=0 numdgt=7 method=trap
TEXT -296 -648 Left 2 ;1kHz low distortion sinewave oscillator.
TEXT -296 -616 Left 2 ;18 Dec 2024.