In Reply to: Quad video splitter posted by Huib Vogel on 01/29/00 at 12:53 PM:
: I am looking for a good electronic schematic and/or reasonable priced module of a video (black and white)quad splitter: 4 B/W CCD camera's simult. on one 14 inch monitor.
: My name is Huib Vogel, The Netherlands tel. (0)341-358579. E-mail: firstname.lastname@example.org
The simplest possible signal splitter, if it might serve your purpose, is merely a star of resistors. A two way spliiter would comprise three resistors, a three way would comprise four resistors and so on. The following program is GWBASIC finds the particular resistor value which should be used in each leg of a star given the impedance level (50 or 75 ohms as shown here), the number of outputs and the signal attenuation you get from input to output. The input impedance of a star which is loaded on each output by the characterisitc impedance of the load is exactly that; the characteristic impedance of the load.
10 CLS:SCREEN 9:COLOR 15,1:C$="Zo= ## ohms split # ways "
20 PRINT "save "+CHR$(34)+"splitter.bas"+CHR$(34):PRINT
30 PRINT "save "+CHR$(34)+"a:\splitter.bas"+CHR$(34):PRINT:PRINT
40 C$=C$+"uses # legs @ ##.## ohms per leg --> ###.## dB loss":GOTO 70
50 FOR N=2 TO 6:R2=R1*(N-1)/(N+1):HDIV=R1/(R1+R2*(N+1))
60 HDB=20*LOG(HDIV)/2.302585:PRINT USING C$;R1,N,N+1,R2,HDB:NEXT N:PRINT:RETURN
70 FOR R1=50 TO 75 STEP 25:GOSUB 50:NEXT R1
John Dunn - President