A 0..5 VOlt aprox 16Hz osc with no L in it. - phaseshiftEmitter.asc [1/1]

On Tuesday, 21 January 2014 15:22:27 UTC+11, Maynard A. Philbrook Jr. wrot e:

example uses no more than 2 ma's over the output, give or take a little.

Distinctly imperfect. The output at the emitter of Q2 bottoms on every cycle.

It's easy enough to fix - see below - but the harmonic content is still pretty high. This class of oscillators always gets its amplitude control by clipping at the rails, and this always introduces harmonic content - and fairly high frequency harmonic content at that.

Baxandall's paper on his Class-D oscillator reviews class-C oscillators, and makes much the same point.

Version 4 SHEET 1 880 680 WIRE 176 -144 -128 -144 WIRE 256 -144 176 -144 WIRE 352 -144 256 -144 WIRE 176 -112 176 -144 WIRE 256 -96 256 -144 WIRE 176 -16 176 -32 WIRE 256 -16 256 -32 WIRE 256 -16 176 -16 WIRE 176 0 176 -16 WIRE -128 16 -128 -144 WIRE 352 64 352 -144 WIRE -16 80 -48 80 WIRE 64 80 48 80 WIRE 128 80 64 80 WIRE -128 112 -128 96 WIRE 128 112 128 80 WIRE 176 112 176 80 WIRE 176 112 128 112 WIRE 256 112 256 -16 WIRE 288 112 256 112 WIRE 176 128 176 112 WIRE -48 144 -48 80 WIRE -48 144 -144 144 WIRE 112 176 96 176 WIRE -144 208 -144 144 WIRE -128 208 -144 208 WIRE -112 208 -128 208 WIRE -16 208 -48 208 WIRE 64 208 64 160 WIRE 64 208 48 208 WIRE 96 208 96 176 WIRE 96 208 64 208 WIRE -128 224 -128 208 WIRE -16 224 -16 208 WIRE 352 240 352 160 WIRE 176 320 176 224 WIRE -128 336 -128 304 WIRE -16 336 -16 304 WIRE 176 336 176 320 FLAG -128 112 0 FLAG -16 336 0 FLAG -128 336 0 FLAG 176 320 0 FLAG 352 320 0 SYMBOL res 48 64 R0 SYMATTR InstName R2 SYMATTR Value 130k SYMBOL voltage -128 0 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V1 SYMATTR Value 6 SYMBOL cap 48 192 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3

SYMBOL res 160 -128 R0 SYMATTR InstName R4 SYMATTR Value 390 SYMBOL res -32 208 R0 WINDOW 0 55 52 Left 2 SYMATTR InstName R3 SYMATTR Value 470 SYMBOL cap -48 192 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1

SYMBOL res -144 208 R0 WINDOW 0 41 51 Left 2 SYMATTR InstName R5 SYMATTR Value 470 SYMBOL cap 48 64 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2

SYMBOL npn 112 128 R0 SYMATTR InstName Q1 SYMATTR Value 2N3904 SYMBOL npn 288 64 R0 SYMATTR InstName Q2 SYMATTR Value 2N2222 SYMBOL res 336 224 R0 SYMATTR InstName R6 SYMATTR Value 100 SYMBOL cap 240 -96 R0 SYMATTR InstName C4

SYMBOL res 160 -16 R0 SYMATTR InstName R1 SYMATTR Value 68 TEXT -96 -168 Left 2 !.tran 1 startup

So ? This is to drive something that won't see the flats.. but that can be fixed, even though it isn't required.

Jesus, it wasn't meant to be perfect, but it's a far better replacement than taking a square wave and trying to get something close to a sine wave..

Jamie

On Wednesday, 22 January 2014 09:27:26 UTC+11, Maynard A. Philbrook Jr. wr ote:

his example uses no more than 2 ma's over the output, give or take a little .

e fixed, even though it isn't required.

The OP has been remarkably unspecific about what he is doing with the outpu t. Claiming that "he won't see the flats" is pure guesswork.

l pretty high. This class of oscillators always gets its amplitude control by clipping at the rails, and this always introduces harmonic content - an d fairly high frequency harmonic content at that.

than taking a square wave and trying to get something close to a sine wave. .

That depends on the application, about which we know very little. Filterin g a square wave does get rid of the higher harmonics very effectively, and at least with a square wave these higher harmonics are well-defined.