System and method for processing communication signals in a communication system having a detector for detecting a parameter of a communication signal. Mounted within the evacuated envelope are a cathode and a rotatbly supported anode. A cylindrical section of the male connecting member is formed integrally with the mounting section and is insertable into and is frictionally rotatable in the accommodation space. The receiver includes a processor that is used to receive the combined control data and digital audio signal and to process the control data to perform a user pre-defined function. The first shape enables the first keys to be used by one of the thumbs of a user, while the second shape of the second keys enables the second keys to be used by the other thumb of the user. According to a specific embodiment, one side of a varactor couples to the tank circuit and the other side is coupled either to ground or to the positive power supply VDD without introducing any series parasitic resistance.