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COMPENSATION FOR THE CAPACITANCE OF THE CAT5 CABLE ON THE OP AMP INPUT.
U202 IS A RAIL SPLITTER TO ESTABLISH LOCAL DC GROUND.  THIS RAIL SPLITTER
MUST SUPPLY THE DC COMPONENT OF THE OUTPUT SIGNAL FROM U201.  THE DC SUPPLY
VOLTAGE CAN BE ANYTHING FROM ABOUT 0 TO 24 V.  SUPPLY CURRENT FOR BOTH THE
PREAMP AND THE SUMMING AMP TOGETHER IS ABOUT 35 MA.  A HIGHER SUPPLY
VOLTAGE WILL ALLOW THE OP AMP OUTPUTS TO SWING FURTHER WITHOUT SATURATING
ON STRONG LOCAL SIGNALS, BUT IN NO CASE SHOULD THE OP AMP MAXIMUM RATING OF
ƒ  QST DE W1AW  ‰
24 V BE EXCEEDED.  A SPLIT SUPPLY R5 V TO R12 V CAN ALSO BE USED, IN WHICH
CASE THE RAIL SPLITTER OP AMP CAN BE OMITTED.  CONSTRUCTION  SMALL PRINTED
CIRCUIT BOARDS PC BOARDS WERE FABRICATED FOR THE CIRCUITS AS SHOWN IN
FIGURE 4.  OTHERS SHOULD BE ABLE TO MAKE THEIR OWN BOARDS USING ONE OF THE
PROTOTYPING SERVICES SUCH AS EXPRESSPCB.  THE CIRCUITS CAN ALSO BE BUILT
DEAD BUG STYLE ON SMALL PIECES OF COPPER CLAD BOARD.  THE PREAMP CIRCUIT IS
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