The following is a simple [absolutely made up, stupid topology, but simulation predicts it oscillates] RC oscillator that seems to want to run slightly under 400Hz. Because it is an RC oscillator, how does one determine the phase noise, or jitter, or however one specs this thing by using LTspice?
I used a simple .tranoise model and it shows/predicts in a spectral plot the sidebands for this oscillator, but how would I find the expected value using only .tran and .noise? Or is there some calculation one uses?
Version 4 SHEET 1 27404 860 WIRE 2304 -1072 1920 -1072 WIRE 2416 -1072 2368 -1072 WIRE 1920 -864 1920 -1072 WIRE 2176 -864 1920 -864 WIRE 2416 -864 2416 -1072 WIRE 2416 -864 2256 -864 WIRE 2240 -800 2192 -800 WIRE 2192 -768 2192 -800 WIRE 1696 -752 1440 -752 WIRE 1792 -752 1760 -752 WIRE 1920 -752 1920 -864 WIRE 1920 -752 1872 -752 WIRE 2160 -752 1920 -752 WIRE 1440 -736 1440 -752 WIRE 2416 -736 2416 -864 WIRE 2416 -736 2224 -736 WIRE 2528 -736 2416 -736 WIRE 2624 -736 2528 -736 WIRE 2688 -736 2624 -736 WIRE 2704 -736 2688 -736 WIRE 2160 -720 2112 -720 WIRE 2528 -704 2528 -736 WIRE 2624 -704 2624 -736 WIRE 2192 -672 2192 -704 WIRE 2240 -672 2192 -672 WIRE 1440 -624 1440 -656 WIRE 2528 -592 2528 -640 WIRE 2624 -592 2624 -624 WIRE 2112 -512 2112 -720 WIRE 2112 -512 1952 -512 WIRE 2160 -512 2112 -512 WIRE 2288 -512 2224 -512 WIRE 2416 -512 2416 -736 WIRE 2416 -512 2368 -512 WIRE 1952 -496 1952 -512 WIRE 1376 -464 1360 -464 WIRE 1424 -464 1376 -464 WIRE 1520 -464 1504 -464 WIRE 1552 -464 1520 -464 WIRE 1680 -464 1632 -464 WIRE 1696 -464 1680 -464 WIRE 1520 -400 1520 -464 WIRE 1952 -352 1952 -416 FLAG 1376 -464 Vcc FLAG 2240 -800 Vcc FLAG 1680 -464 Vss FLAG 2240 -672 Vss FLAG 2624 -592 0 FLAG 2528 -592 0 FLAG 1520 -400 0 FLAG 2688 -736 out FLAG 1440 -624 0 FLAG 1952 -352 0 SYMBOL Opamps\\LT1115 2192 -800 R0 SYMATTR InstName U1 SYMBOL Misc\\battery 1408 -464 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 -32 56 VBottom 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName Vpos SYMATTR Value 9Vdc SYMBOL Misc\\battery 1536 -464 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 -32 56 VBottom 2 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName Vneg SYMATTR Value 9Vdc SYMBOL res 1936 -512 R0 SYMATTR InstName Rbias SYMATTR Value {Rb} SYMBOL res 2608 -720 R0 SYMATTR InstName Rload SYMATTR Value 2k SYMBOL cap 2512 -704 R0 SYMATTR InstName Cload SYMATTR Value 10pF SYMBOL Misc\\signal 1440 -752 R0 WINDOW 123 24 44 Left 2 WINDOW 39 0 0 Left 2 SYMATTR Value2 AC 1 SYMATTR InstName V1 SYMATTR Value "" SYMBOL res 1776 -736 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName Rin SYMATTR Value 1k SYMBOL res 2384 -528 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName Rboost SYMATTR Value {Rb2} SYMBOL cap 1760 -768 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName Cin
SYMBOL res 2160 -848 R270 WINDOW 0 32 56 VTop 2 WINDOW 3 0 56 VBottom 2 SYMATTR InstName Rfdbk SYMATTR Value 10k SYMBOL cap 2160 -496 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName C1
SYMBOL cap 2304 -1056 R270 WINDOW 0 32 32 VTop 2 WINDOW 3 0 32 VBottom 2 SYMATTR InstName Cfdbk SYMATTR Value 1nF TEXT 2824 -856 Left 2 ;.tran 0 {Tstop} {Tstart} {dt/20}\n.save V(out) TEXT 2856 -800 Left 2 !.options plotwinsize=0;\n.param k=1.38e-23 T=300\n.param fmax=50000 N={2*fmax} \n.param dt={1/2/fmax}\n.param Tstop=1.1 Tstart=0.1\n.param BW=1 TEXT 2824 -920 Left 2 ;.ac dec 200 {BW} {fmax} TEXT 2824 -888 Left 2 !.noise V(out) V1 dec 200 {BW} {fmax} TEXT 2864 -592 Left 2 ;.param N={Tstop*2*fmax} TEXT 2680 -1040 Left 4 ;RC OSCILLATOR using LT1115 TEXT 1968 -408 Left 2 !.param Rb=1k TEXT 2248 -448 Left 2 !.param Rb2=5.1k