Apparatus for determining pen acceleration

摘要

An apparatus for determining pen acceleration for use in a signature vertification system. Capacitive transducer means are mounted in a pen, and change capacitance by an amount which is proportional to pen acceleration. A Blumlein bridge circuit is utilized to measure changes in the capacitance of the transducer means, and the output of the bridge is amplified and demodulated to result in a signal which is proportional to acceleration.