Version 4
SHEET 1 2132 884
WIRE 320 -576 288 -576
WIRE 320 -544 320 -576
WIRE 320 -432 320 -464
WIRE 448 -576 320 -576
WIRE 624 -544 592 -544
WIRE 864 -1056 816 -1056
WIRE 1008 -1056 944 -1056
WIRE 1008 -1024 1008 -1056
WIRE 1008 -912 1008 -944
WIRE 1104 -1056 1008 -1056
WIRE 1104 -1008 1104 -1056
WIRE 1104 -912 1104 -944
WIRE 1136 -1056 1104 -1056
WIRE 1360 -960 1360 -1024
WIRE 1360 -832 1360 -880
WIRE 1472 -1088 1392 -1088
WIRE 1472 -1024 1360 -1024
WIRE 1696 -1040 1648 -1040
FLAG 320 -432 0
FLAG 288 -576 V_SWEEP
IOPIN 288 -576 Out
FLAG 624 -544 V_FM
IOPIN 624 -544 Out
FLAG 1008 -912 0
FLAG 816 -1056 V_FM
IOPIN 816 -1056 In
FLAG 1136 -1056 sig
IOPIN 1136 -1056 Out
FLAG 1392 -1088 sig
IOPIN 1392 -1088 In
FLAG 1696 -1040 vpeak
IOPIN 1696 -1040 Out
FLAG 1104 -912 0
FLAG 1360 -832 0
SYMBOL SpecialFunctions\\modulate 448 -576 R0
WINDOW 3 144 -8 Left 0
WINDOW 0 8 -48 Left 0
WINDOW 123 144 72 Left 0
SYMATTR Value space=0 mark={f0}
SYMATTR InstName A1
SYMATTR Value2 Vhigh={Vdc+Vp} Vlow={Vdc-Vp}
SYMBOL bv 320 -560 R0
WINDOW 3 24 112 Left 0
SYMATTR Value V={f1/f0}*{f2/f1}**(time/Td)
SYMATTR InstName B1
SYMBOL SpecialFunctions\\sample 1552 -1056 R0
SYMATTR InstName A4
SYMBOL cap 1088 -1008 R0
SYMATTR InstName C1
SYMATTR Value 1µ
SYMBOL ind 992 -1040 R0
SYMATTR InstName L1
SYMATTR Value 10m
SYMBOL res 848 -1040 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName R1
SYMATTR Value 100
SYMBOL bv 1360 -976 R0
SYMATTR InstName B2
SYMATTR Value V=u(-ddt(V(sig)))
TEXT 136 -968 Left 0 !.tran 0 {Td} 0
TEXT 136 -1048 Left 0 !.param f0=1k f1=0.1k f2=10k Td=1000m\n.param Vp=.5 Vdc=0
TEXT 416 -384 Left 0 ;Sweep Parameters:\nf0= scale freq  f1= start freq  f2= stop freq\nTd= sweep duration  Vp= sine peak  Vdc= sine offset
TEXT 304 -696 Left 0 ;This circuit demonstrates both an A-device and a B-source \nimplementation of a swept sine source for transient analysis.
TEXT 648 -752 Center 0 ;Swept Sine Redux -  analogspiceman 2005
TEXT 136 -1088 Left 0 !.options plotwinsize=0
TEXT 728 -1128 Left 0 ;Bandpass Filter Under Test
TEXT 144 -1272 Left 0 ;Transient-Analysis With A Swept Sine-Source And A Peak Envelope Detector\nAfter an idea from Gerd Mildner("gxxmxx") and "analogspiceman\n \nWatch V(sig) and V(vpeak).
TEXT 136 -928 Left 0 !.options nomarch
TEXT 1368 -1200 Left 0 ;Poor man's peak detector :-)\n-regards\nGerd
TEXT 136 -1128 Left 0 !.options trtol=1e-3
RECTANGLE Normal 912 -728 384 -776 1
RECTANGLE Normal 1232 -864 640 -1152
RECTANGLE Normal 1056 -288 112 -800