Sine to square wave converter

-0330, Gary wrote:

DC resistance are the same if the line is

at the input

true, even

the

plastic?

Most are :-)

going to measure more

no way an infinite length will have a lower resistance.

Run the LTSpice simulation below, three cases of 1000 miles of RG59-U, terminated. shorted, and open at 1 MHz. You'll find all 3 cases look like

75 ohms. Constants are per Belden data.

LTSpice is free, if you didn't already know that, and runs under WINE, (well at least here it does.)

RG59-U.asc

Version 4 SHEET 1 880 680 WIRE

-128 144 -128 32 WIRE -128 160 -128 144 WIRE -128 320 -128 240 WIRE 48 320 -128

320 WIRE 48 320 48 64 WIRE 80 320 48 320 WIRE 80 320 80 176 WIRE 112 32 -128 32 WIRE 112 64 48 64 WIRE 112 144 -128 144 WIRE 112 176 80 176 WIRE 128 320 80 320 WIRE 128 352 128 320 WIRE 240 176 208 176 WIRE 240 320 128 320 WIRE 240 320 240 176 WIRE 288 64 208 64 WIRE 288 320 240 320 WIRE 288 320 288 64 WIRE 384 32 208 32 WIRE 384 144 208 144 WIRE 384 320 288 320 WIRE 384 320 384 224 FLAG 128 352 0 SYMBOL ltline 160 160 R0 SYMATTR InstName O1 SYMATTR Value RG59U SYMBOL voltage

-128 144 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value SINE(0 1 1e6) SYMBOL res 368 240 M180 WINDOW 0 36 76 Left 0 WINDOW

3 36 40 Left 0 SYMATTR InstName R2 SYMATTR Value 75 SYMBOL ltline 160 48 R0 SYMATTR InstName O2 SYMATTR Value RG59U TEXT -152 456 Left 0 !.model RG59U LTRA(len=5.28e6 R=51.6e-3 L=0.115u C=20.5p) TEXT -162 506 Left 0 !.tran 0 1m 0 1u TEXT 496 456 Left 0 ;(Belden 8263)

RG59U.plt

[Transient Analysis] { Npanes: 3 Active Pane: 2 { traces: 1 {524290,0,"v(n001)/Ia(O1)"} X: ('u',0,0,8e-005,0.0008) Y[0]: (' ',0,0,10,100) Y[1]: ('_',0,1e+308,0,-1e+308) Units: "Ohm" (' ',0,0,0,0,10,100) Log: 0 0 0 GridStyle: 1 }, { traces: 1 {524291,0,"v(n001)/Ia(O2)"} X: ('u',0,0,8e-005,0.0008) Y[0]: (' ',0,0,10,100) Y[1]: ('_',0,1e+308,0,-1e+308) Units: "Ohm" (' ',0,0,0,0,10,100) Log: 0 0 0 GridStyle: 1 }, { traces: 1 {524292,0,"v(n001)/Ia(O3)"} X: ('u',0,0,8e-005,0.0008) Y[0]: (' ',0,0,10,100) Y[1]: ('_',0,1e+308,0,-1e+308) Units: "Ohm" (' ',0,0,0,0,10,100) Log: 0 0 0 GridStyle: 1 } }

--
"Electricity is of two kinds, positive and
negative. The difference
is, I presume, that one comes a little more expensive,
but is more
durable; the other is a cheaper thing, but the moths get into it."
 
                                           (Stephen Leacock)