An apparatus is disclosed for performing real time videoaudio encoding on a single chip. This method includes sensing deformation of a portion of the articulated arm when the arm is placed under a load, this deformation causing an error in the measurement made by the CMM, and correcting such error in response to the sensed deformation. A communication manner suitable for content of message may be selected for sending the message, thus bringing convenience to users, and lowering requirements on terminals. The protection chip further outputs a high level signal to the sequence controller upon receiving an induction signal from the induction module. The mercury-199 isotope content of the mercury is lower than that in natural mercury and the mercury-201 andor mercury-204 isotopes are greater than those in natural mercury. Alternatively, the sample velocity through the turn portion may be controlled so as to reduce band broadening.