Re: Not particularly low distortion 1kHz sine wave oscillator

"Bill Sloman" <bill.sloman@ieee.org> wrote in message news:viot8j$mt28$1@dont-email.me...

On 4/12/2024 4:29 pm, Edward Rawde wrote:

"Bill Sloman" <bill.sloman@ieee.org> wrote in message news:viokrg$l9s1$1@dont-email.me...

Edward Rawde has posted a number of low distortion 1kHz sine wave oscillators as LTSpice simulation, and John May has posted a
couple of much low distortion examples.
>
As designs they are bit opaque. I've posted my own attempts.
>
Here's another.

>
Are you sure that's the correct circuit Bill?
>
What I'm seeing has U1 displaced but easy to correct but U2 output is not connected and the feedback from U5 is hanging in mid
air
above an unconnected current mirror with nothing connected the the FET gate circuit.

>
It probably isn't. Here's much the same circuit tweaked to give the 1kz fundamental closer to 0 dB - 1V rms. The extra componets
are R8, R9 and R28 at the top right of the circuit.
>

Ok I had to adjust the position of U1 and connect the + pin.
FFT shows noise at 70dB down.

I decided to find out whether a discrete circuit using a high voltage rail would have better distortion performance.
This circuit has no gain control yet but if you take a sample when the output is at about 1V pk-pk you get 100dB down at 2kHz as
long as you keep your fingers away from the supply rail. If I could just get rid of 2kHz it would be 130dB down.

Version 4
SHEET 1 2740 1600
WIRE 288 272 224 272
WIRE 464 272 288 272
WIRE 752 272 464 272
WIRE 1136 272 752 272
WIRE 1376 272 1136 272
WIRE 1664 272 1376 272
WIRE 224 320 224 272
WIRE 464 320 464 272
WIRE 1136 320 1136 272
WIRE 1376 320 1376 272
WIRE 752 416 752 272
WIRE 1664 416 1664 272
WIRE 224 464 224 400
WIRE 320 464 224 464
WIRE 464 464 464 400
WIRE 688 464 464 464
WIRE 1136 464 1136 400
WIRE 1232 464 1136 464
WIRE 1376 464 1376 400
WIRE 1600 464 1376 464
WIRE 224 544 224 464
WIRE 320 544 320 464
WIRE 1136 544 1136 464
WIRE 1232 544 1232 464
WIRE 512 624 384 624
WIRE 752 624 752 512
WIRE 752 624 576 624
WIRE 1424 624 1296 624
WIRE 1664 624 1664 512
WIRE 1664 624 1488 624
WIRE -304 656 -304 608
WIRE 464 688 464 464
WIRE 1376 688 1376 464
WIRE 224 736 224 624
WIRE 384 736 384 624
WIRE 384 736 224 736
WIRE 400 736 384 736
WIRE 1136 736 1136 624
WIRE 1296 736 1296 624
WIRE 1296 736 1136 736
WIRE 1312 736 1296 736
WIRE 224 768 224 736
WIRE 1136 768 1136 736
WIRE -304 800 -304 736
WIRE 160 816 80 816
WIRE 320 816 320 608
WIRE 464 816 464 784
WIRE 464 816 320 816
WIRE 1072 816 992 816
WIRE 1232 816 1232 608
WIRE 1376 816 1376 784
WIRE 1376 816 1232 816
WIRE 1664 816 1664 624
WIRE 1840 816 1664 816
WIRE 1952 816 1840 816
WIRE 464 832 464 816
WIRE 1376 832 1376 816
WIRE 752 864 752 624
WIRE 880 864 752 864
WIRE 80 912 80 816
WIRE 128 912 80 912
WIRE 224 912 224 864
WIRE 224 912 192 912
WIRE 992 912 992 816
WIRE 1040 912 992 912
WIRE 1136 912 1136 864
WIRE 1136 912 1104 912
WIRE 224 928 224 912
WIRE 320 928 224 928
WIRE 1136 928 1136 912
WIRE 1232 928 1136 928
WIRE 80 944 80 912
WIRE 464 944 464 912
WIRE 544 944 464 944
WIRE 992 944 992 912
WIRE 1376 944 1376 912
WIRE 1456 944 1376 944
WIRE 224 960 224 928
WIRE 464 960 464 944
WIRE 1136 960 1136 928
WIRE 1376 960 1376 944
WIRE 752 976 752 864
WIRE 752 976 640 976
WIRE 1664 976 1664 816
WIRE 1664 976 1552 976
WIRE 1664 992 1664 976
WIRE 1776 992 1664 992
WIRE 640 1024 640 976
WIRE 1552 1024 1552 976
WIRE 1776 1024 1776 992
WIRE 80 1072 80 1024
WIRE 464 1072 464 1040
WIRE 464 1072 80 1072
WIRE 992 1072 992 1024
WIRE 1376 1072 1376 1040
WIRE 1376 1072 992 1072
WIRE 224 1104 224 1040
WIRE 224 1104 80 1104
WIRE 1136 1104 1136 1040
WIRE 1136 1104 992 1104
WIRE 80 1136 80 1104
WIRE 224 1136 224 1104
WIRE 464 1136 464 1072
WIRE 544 1136 544 944
WIRE 752 1136 752 976
WIRE 992 1136 992 1104
WIRE 1136 1136 1136 1104
WIRE 1376 1136 1376 1072
WIRE 1456 1136 1456 944
WIRE 1664 1136 1664 992
WIRE 80 1248 80 1200
WIRE 80 1248 48 1248
WIRE 224 1248 224 1216
WIRE 224 1248 80 1248
WIRE 464 1248 464 1216
WIRE 464 1248 224 1248
WIRE 544 1248 544 1200
WIRE 544 1248 464 1248
WIRE 752 1248 752 1216
WIRE 752 1248 544 1248
WIRE 992 1248 992 1200
WIRE 992 1248 752 1248
WIRE 1136 1248 1136 1216
WIRE 1136 1248 992 1248
WIRE 1376 1248 1376 1216
WIRE 1376 1248 1136 1248
WIRE 1456 1248 1456 1200
WIRE 1456 1248 1376 1248
WIRE 1664 1248 1664 1216
WIRE 1664 1248 1456 1248
WIRE 48 1264 48 1248
WIRE 320 1328 320 928
WIRE 368 1328 320 1328
WIRE 640 1328 640 1088
WIRE 640 1328 448 1328
WIRE 880 1328 880 864
WIRE 976 1328 880 1328
WIRE 1056 1328 1040 1328
WIRE 1232 1328 1232 928
WIRE 1232 1328 1136 1328
WIRE 1312 1328 1232 1328
WIRE 1360 1328 1312 1328
WIRE 1504 1328 1440 1328
WIRE 1552 1328 1552 1088
WIRE 1552 1328 1504 1328
WIRE 1312 1424 1312 1328
WIRE 1376 1424 1312 1424
WIRE 1504 1424 1504 1328
WIRE 1504 1424 1440 1424
WIRE 320 1520 320 1328
WIRE 688 1520 320 1520
WIRE 1776 1520 1776 1088
WIRE 1776 1520 768 1520
FLAG -304 800 0
FLAG -304 608 V+
FLAG 48 1264 0
FLAG 288 272 V+
FLAG 1840 816 output
DATAFLAG 704 624 "round(($)*100)/100"
DATAFLAG 512 944 "round(($)*100)/100"
DATAFLAG 416 1072 "round(($)*100)/100"
DATAFLAG 128 816 "round(($)*100)/100"
DATAFLAG 272 928 "round(($)*100)/100"
DATAFLAG 176 1104 "round(($)*100)/100"
DATAFLAG 272 464 "round(($)*100)/100"
DATAFLAG 272 736 "round(($)*100)/100"
DATAFLAG 416 816 "round(($)*100)/100"
DATAFLAG 512 464 "round(($)*100)/100"
DATAFLAG 1616 624 "round(($)*100)/100"
DATAFLAG 1424 944 "round(($)*100)/100"
DATAFLAG 1328 1072 "round(($)*100)/100"
DATAFLAG 1040 816 "round(($)*100)/100"
DATAFLAG 1184 928 "round(($)*100)/100"
DATAFLAG 1088 1104 "round(($)*100)/100"
DATAFLAG 1184 464 "round(($)*100)/100"
DATAFLAG 1184 736 "round(($)*100)/100"
DATAFLAG 1328 816 "round(($)*100)/100"
DATAFLAG 1424 464 "round(($)*100)/100"
SYMBOL voltage -304 640 R0
WINDOW 123 0 0 Left 0
WINDOW 39 10 135 Left 2
WINDOW 0 12 7 Left 2
WINDOW 3 15 104 Left 2
SYMATTR InstName V1
SYMATTR Value 96
SYMBOL res 784 1504 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R14
SYMATTR Value 9841
SYMBOL res 208 304 R0
WINDOW 3 36 73 Left 2
SYMATTR Value 47k
SYMATTR InstName R10
SYMBOL npn 160 768 R0
SYMATTR InstName Q1
SYMATTR Value BC846B
SYMBOL res 208 528 R0
WINDOW 0 -41 35 Left 2
WINDOW 3 -64 67 Left 2
SYMATTR InstName R11
SYMATTR Value 150k
SYMBOL npn 688 416 R0
SYMATTR InstName Q2
SYMATTR Value BC846B
SYMBOL res 448 304 R0
WINDOW 3 35 73 Left 2
SYMATTR Value 22k
SYMATTR InstName R15
SYMBOL npn 400 688 R0
SYMATTR InstName Q3
SYMATTR Value BC846B
SYMBOL polcap 304 544 R0
SYMATTR InstName C1
SYMATTR Value 1�
SYMBOL res 208 944 R0
WINDOW 3 35 67 Left 2
SYMATTR Value 470
SYMATTR InstName R16
SYMBOL res 208 1120 R0
WINDOW 3 37 67 Left 2
SYMATTR Value 39k
SYMATTR InstName R19
SYMBOL res 64 928 R0
WINDOW 0 -41 40 Left 2
WINDOW 3 -66 68 Left 2
SYMATTR InstName R20
SYMATTR Value 270k
SYMBOL cap 192 896 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C6
SYMATTR Value 470p
SYMBOL polcap 64 1136 R0
SYMATTR InstName C7
SYMATTR Value 22�
SYMBOL res 736 1120 R0
WINDOW 0 36 38 Left 2
WINDOW 3 36 72 Left 2
SYMATTR InstName R21
SYMATTR Value 3.3k
SYMBOL cap 576 608 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C8
SYMATTR Value 10p
SYMBOL res 448 944 R0
WINDOW 0 -52 35 Left 2
WINDOW 3 -54 62 Left 2
SYMATTR InstName R22
SYMATTR Value 5.6k
SYMBOL res 448 1120 R0
WINDOW 0 -53 28 Left 2
WINDOW 3 -50 58 Left 2
SYMATTR InstName R23
SYMATTR Value 6.8k
SYMBOL res 448 816 R0
WINDOW 0 -59 43 Left 2
WINDOW 3 -59 70 Left 2
SYMATTR InstName R24
SYMATTR Value 2.2k
SYMBOL res 464 1312 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R25
SYMATTR Value 10k
SYMBOL polcap 624 1024 R0
SYMATTR InstName C11
SYMATTR Value 1�
SYMBOL polcap 528 1136 R0
SYMATTR InstName C12
SYMATTR Value 100�
SYMBOL res 1344 1344 R270
WINDOW 0 32 56 VTop 2
WINDOW 3 0 56 VBottom 2
SYMATTR InstName R13
SYMATTR Value 16K
SYMBOL res 1152 1312 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R26
SYMATTR Value 8K
SYMBOL cap 1376 1440 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName C5
SYMATTR Value 10n
SYMBOL cap 1040 1312 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C9
SYMATTR Value 20n
SYMBOL res 1120 304 R0
WINDOW 3 36 73 Left 2
SYMATTR Value 47k
SYMATTR InstName R29
SYMBOL npn 1072 768 R0
SYMATTR InstName Q4
SYMATTR Value BC846B
SYMBOL res 1120 528 R0
WINDOW 0 -41 35 Left 2
WINDOW 3 -64 67 Left 2
SYMATTR InstName R30
SYMATTR Value 150k
SYMBOL npn 1600 416 R0
SYMATTR InstName Q5
SYMATTR Value BC846B
SYMBOL res 1360 304 R0
WINDOW 3 35 73 Left 2
SYMATTR Value 22k
SYMATTR InstName R31
SYMBOL npn 1312 688 R0
SYMATTR InstName Q6
SYMATTR Value BC846B
SYMBOL polcap 1216 544 R0
SYMATTR InstName C10
SYMATTR Value 1�
SYMBOL res 1120 944 R0
WINDOW 3 35 67 Left 2
SYMATTR Value 470
SYMATTR InstName R32
SYMBOL res 1120 1120 R0
WINDOW 3 37 67 Left 2
SYMATTR Value 39k
SYMATTR InstName R33
SYMBOL res 976 928 R0
WINDOW 0 -41 40 Left 2
WINDOW 3 -66 68 Left 2
SYMATTR InstName R34
SYMATTR Value 270k
SYMBOL cap 1104 896 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C13
SYMATTR Value 470p
SYMBOL polcap 976 1136 R0
SYMATTR InstName C14
SYMATTR Value 22�
SYMBOL res 1648 1120 R0
WINDOW 0 36 38 Left 2
WINDOW 3 36 72 Left 2
SYMATTR InstName R35
SYMATTR Value 3.3k
SYMBOL cap 1488 608 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C15
SYMATTR Value 10p
SYMBOL res 1360 944 R0
WINDOW 0 -52 35 Left 2
WINDOW 3 -54 62 Left 2
SYMATTR InstName R36
SYMATTR Value 5.6k
SYMBOL res 1360 1120 R0
WINDOW 0 -53 28 Left 2
WINDOW 3 -50 58 Left 2
SYMATTR InstName R37
SYMATTR Value 6.8k
SYMBOL res 1360 816 R0
WINDOW 0 -59 43 Left 2
WINDOW 3 -59 70 Left 2
SYMATTR InstName R38
SYMATTR Value 2.2k
SYMBOL polcap 1536 1024 R0
SYMATTR InstName C16
SYMATTR Value 1�
SYMBOL polcap 1440 1136 R0
SYMATTR InstName C17
SYMATTR Value 100�
SYMBOL polcap 1760 1024 R0
SYMATTR InstName C2
SYMATTR Value 1�
TEXT -608 1224 Left 2 !.tran 0 4 2.5 1u
TEXT -608 1176 Left 2 !.options plotwinsize=0 numdgt=7 method=trap
TEXT -408 440 Left 2 ;1kHz low distortion sinewave oscillator.
TEXT -400 472 Left 2 ;2 Dec 2024.