Source : Free On-Line Dictionary of Computing

VCC filtering
     
         A technique for reducing the amount of {Radio
        Frequency Interference} spread via power supply connections.
        {VCC} is a common name for the non-{ground} power supply line
        in circuits based on {bipolar transistors}.
     
        When part of a circuit generates lots of radio-frequency
        noise, that portion of the {power plane} can be isolated from
        the rest of the circuit and power delivered to it via a {low
        pass filter}, usually a {PI filter}, as shown in the diagram
        below.
     
              source   ________inductor_________   load
        		  |                |
        	      capacitor        capacitor
        		  |                |
        	       ground           ground
     
        This helps to shield the rest of the circuit from the noise
        generated by the load.
     
        (1998-01-26)