What is this oscillator configuration called?
It seems to have some good and useful features: easy to control XTAL drive level; operates in series resonant mode; differential square-ish wave output with fast rise time; very good amplitude stability versus supply voltage variation; no relaxation mode if crystal removed; no need to tune-out C0 holder capacitance; simple single-point power-supply decoupling.
What are the disadvantages? Two active devices = more noise? But the Butler and Driscoll circuits use two active devices. No LC frequency selectivity to force XTAL onto correct harmonic? But that could be added...
TIA
LTSpice .ASC file:
Version 4 SHEET 1 928 744 WIRE -80 -160 -128 -160 WIRE 48 -160 0 -160 WIRE 96 -160 48 -160 WIRE 224 -160 176 -160 WIRE 48 -112 48 -160 WIRE 48 0 48 -32 WIRE -128 48 -128 -160 WIRE -16 48 -128 48 WIRE 224 48 224 -160 WIRE 224 48 112 48 WIRE -128 128 -128 48 WIRE 224 128 224 48 WIRE -16 176 112 48 WIRE -16 176 -64 176 WIRE 112 176 -16 48 WIRE 160 176 112 176 WIRE -128 272 -128 224 WIRE 32 272 -128 272 WIRE 224 272 224 224 WIRE 224 272 96 272 WIRE -128 384 -128 272 WIRE -80 384 -128 384 WIRE 32 384 0 384 WIRE 112 384 96 384 WIRE 224 384 224 272 WIRE 224 384 192 384 WIRE 224 432 224 384 WIRE 352 432 224 432 WIRE -128 480 -128 384 WIRE 224 480 224 432 WIRE 352 480 352 432 WIRE -128 608 -128 560 WIRE 224 608 224 560 WIRE 352 608 352 560 FLAG 48 0 0 FLAG 224 608 0 FLAG 352 608 0 FLAG -128 608 0 SYMBOL voltage 48 -128 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V2 SYMATTR Value 5 SYMBOL npn 160 128 R0 SYMATTR InstName Q1 SYMATTR Value 2N3904 SYMBOL npn -64 128 M0 SYMATTR InstName Q2 SYMATTR Value 2N3904 SYMBOL current 352 480 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName I2 SYMATTR Value SINE(0 1e-3 10e6 0 0 0 10) SYMBOL ind -96 400 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L1 SYMATTR Value 0.0253303 SYMATTR SpiceLine Rpar=1e300 SYMBOL cap 96 368 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C1 SYMATTR Value 10f SYMBOL res 208 368 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R1 SYMATTR Value 20 SYMBOL res 192 -176 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R2 SYMATTR Value 1k SYMBOL res 16 -176 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R3 SYMATTR Value 1k SYMBOL cap 96 256 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C0 SYMATTR Value 5p SYMBOL res 208 464 R0 SYMATTR InstName R4 SYMATTR Value 3k3 SYMBOL res -144 464 R0 SYMATTR InstName R5 SYMATTR Value 3k3 TEXT 16 600 Left 0 !.tran 1m