Version 4.1
SHEET 1 3436 728
WIRE -32 -112 -176 -112
WIRE 32 -112 -32 -112
WIRE 64 -112 32 -112
WIRE 80 -112 64 -112
WIRE 192 -112 144 -112
WIRE 304 -112 272 -112
WIRE 416 -112 384 -112
WIRE 480 -112 416 -112
WIRE 544 -112 480 -112
WIRE 608 -112 544 -112
WIRE 656 -112 608 -112
WIRE -176 -96 -176 -112
WIRE 544 -16 544 -112
WIRE -176 0 -176 -16
WIRE 64 0 64 -112
WIRE 176 0 64 0
WIRE 416 0 416 -112
WIRE 416 0 240 0
WIRE 656 0 656 -112
WIRE -32 16 -32 -112
WIRE 32 112 32 -112
WIRE 192 112 32 112
WIRE 480 112 480 -112
WIRE 480 112 256 112
WIRE -176 192 -176 80
WIRE -32 192 -32 80
WIRE -32 192 -176 192
WIRE 160 192 -32 192
WIRE 544 192 544 48
WIRE 544 192 160 192
WIRE 656 192 656 80
WIRE 656 192 544 192
WIRE 160 208 160 192
WIRE -16 368 -160 368
WIRE 48 368 -16 368
WIRE 80 368 48 368
WIRE 96 368 80 368
WIRE 208 368 160 368
WIRE 320 368 288 368
WIRE 432 368 400 368
WIRE 480 368 432 368
WIRE 560 368 480 368
WIRE 576 368 560 368
WIRE 656 368 576 368
WIRE 704 368 656 368
WIRE 720 368 704 368
WIRE 832 368 784 368
WIRE 944 368 912 368
WIRE 1040 368 1024 368
WIRE 1104 368 1040 368
WIRE 1184 368 1104 368
WIRE 1248 368 1184 368
WIRE 1296 368 1248 368
WIRE -160 384 -160 368
WIRE 560 464 560 368
WIRE 1184 464 1184 368
WIRE -160 480 -160 464
WIRE 80 480 80 368
WIRE 192 480 80 480
WIRE 432 480 432 368
WIRE 432 480 256 480
WIRE 704 480 704 368
WIRE 816 480 704 480
WIRE 1040 480 1040 368
WIRE 1040 480 880 480
WIRE 1296 480 1296 368
WIRE -16 496 -16 368
WIRE 48 576 48 368
WIRE 192 576 48 576
WIRE 480 576 480 368
WIRE 480 576 256 576
WIRE 656 576 656 368
WIRE 832 576 656 576
WIRE 1104 576 1104 368
WIRE 1104 576 896 576
WIRE -160 640 -160 560
WIRE -16 640 -16 560
WIRE -16 640 -160 640
WIRE 176 640 -16 640
WIRE 560 640 560 528
WIRE 560 640 176 640
WIRE 1184 640 1184 528
WIRE 1184 640 560 640
WIRE 1296 640 1296 560
WIRE 1296 640 1184 640
WIRE 176 656 176 640
FLAG 160 208 0
FLAG 608 -112 1_section_out
FLAG 176 656 0
FLAG 1248 368 2_section_out
FLAG 576 368 2_section_int
SYMBOL cap -48 16 R0
SYMATTR InstName C1
SYMATTR Value 33pF
SYMBOL cap 528 -16 R0
SYMATTR InstName C2
SYMATTR Value 33pF
SYMBOL cap 240 -16 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C3
SYMATTR Value 6p
SYMBOL cap 144 -128 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C4
SYMATTR Value 0.02p
SYMBOL ind 288 -128 R90
WINDOW 0 5 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName L1
SYMATTR Value 858.905µH
SYMATTR SpiceLine Rser=1m
SYMBOL res 400 -128 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 50R
SYMBOL res 640 -16 R0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL voltage -176 -16 R0
SYMATTR InstName V1
SYMATTR Value AC 1.
SYMBOL res -192 -112 R0
SYMATTR InstName R3
SYMATTR Value 50R
SYMBOL cap -32 496 R0
SYMATTR InstName C5
SYMATTR Value 33pF
SYMBOL cap 544 464 R0
SYMATTR InstName C6
SYMATTR Value 33pF
SYMBOL cap 256 464 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C7
SYMATTR Value 6p
SYMBOL cap 160 352 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C8
SYMATTR Value 0.02p
SYMBOL ind 304 352 R90
WINDOW 0 5 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName L2
SYMATTR Value 858.905µH
SYMATTR SpiceLine Rser=1m
SYMBOL res 416 352 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R4
SYMATTR Value 50R
SYMBOL voltage -160 464 R0
SYMATTR InstName V2
SYMATTR Value AC 1.
SYMBOL res -176 368 R0
SYMATTR InstName R6
SYMATTR Value 50R
SYMBOL cap 1168 464 R0
SYMATTR InstName C9
SYMATTR Value 33pF
SYMBOL cap 880 464 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C10
SYMATTR Value 6p
SYMBOL cap 784 352 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C11
SYMATTR Value 0.02p
SYMBOL ind 928 352 R90
WINDOW 0 5 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName L3
SYMATTR Value 858.905µH
SYMATTR SpiceLine Rser=1m
SYMBOL res 1040 352 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R7
SYMATTR Value 50R
SYMBOL res 1280 464 R0
SYMATTR InstName R8
SYMATTR Value 1k
SYMBOL cap 256 96 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C12
SYMATTR Value 4pF
SYMBOL cap 256 560 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C13
SYMATTR Value 4pF
SYMBOL cap 896 560 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C14
SYMATTR Value 4pF
TEXT -176 712 Left 2 !.ac dec 100000 100k 100Meg
TEXT -272 -472 Left 5 ;A 38.4Mhz Crystal filter
TEXT 120 -200 Left 2 ;crystal equivalent cct
TEXT 128 296 Left 2 ;crystal equivalent cct
TEXT 728 288 Left 2 ;crystal equivalent cct
TEXT 1392 -64 Left 4 ;Selecting the crystal
TEXT 1408 336 Left 4 ;about the crystal equivalent cct
TEXT 1416 400 Left 2 ;the three cct components in series are called the motional capacitance, \nthe motional inductance, and the motional resistance.\nthese are the characteristics of the crystal vibrating.\nthe other capacitance is called the shunt capacitance and is a\ncharacteristic of the crystal electrodes and holder.\nThe other C in parallel with the crystal shunt C, is the unaviodable \nstray cct C.
TEXT 256 144 Left 2 ;(stray C)
TEXT 256 600 Left 2 ;(stray C)
TEXT 888 600 Left 2 ;(stray C)
TEXT 1392 -280 Left 4 ;instructions
TEXT 1400 -240 Left 2 ;click on run\nthen click on the "1_section_out" net to plot its freq. response\nthen click on the plot window and plot settings/add plot pane\nthen click on the "2_section_out" net to plot its freq. response\nthen in the plot window, zoom in on the spike in the filter response.
TEXT 1400 -16 Left 2 ;the freq chosen for the IF is 38.4 Mhz\nthis the closest freq to 38Mhz with large no's of available crystals
TEXT -288 -320 Left 3 ;I have put motional R in as 50R, this may be incorrect depending on the crystal chosen
TEXT 1408 112 Left 2 ;looking at the 2 section filter.\nthe 3db passband is about 16 khz wide.\nhowever the attenuation outside of the passband is not symmetrical,\nthe rise in attenuation is a lot steeper on the high freq side.\nto get a further 10db of attenuation you have to go \n7khz outside the passband on the high freq side.\nand 28khz outside the passband on the low freq side.
TEXT -296 -408 Left 3 ;the values of the motional L, and motional C, are generally not given on crystal manufacturers datasheets,\nhence the values used here are only estimates.
TEXT 1416 64 Left 4 ;Results
TEXT 1328 648 Left 1 ;You may republish or reuse this circuit implementation and text providing this line and the following lines are included.\nThis circuit implementation designed by Keith Wallbanks. Originally released on analogsimulation.co.uk\nThis circuit is provided as is without warranty of any kind. This text is intended to implement the MIT licence.
RECTANGLE Normal 432 48 48 -176 2
RECTANGLE Normal 448 528 64 320 2
RECTANGLE Normal 1056 528 688 320 2