Abstract: In the present invention a method of compressing a signature signal is disclosed. The signature signal is divided into a plurality of signature segment signals where each segment is encoded by using a modified ring-encoding method, such that the total number of grid points along the perimeter of all the rings can be stored in an 8-bit byte. In one embodiment of the method of the present invention, a Fibonacci series is used to determine the relative spacing of the rings. The present invention also discloses a method and apparatus for electronically processing a POS transaction with a human signature for verification of the transaction, as well as for request of extension of credit by a credit company. The signature is electronically captured, compressed and combined with a transaction signal which is representative of the transaction. The record signal is then processed by the credit company for verification of the transaction or for requesting extension of credit.

Abstract: A fully differential sigma-delta signal processor for use in high-speed voiceband or higher-frequency applications. The processor receives the two polarities of a differential input signal and passes them to a differential-amplifier integrator through a switched sampling capacitor arrangement. The capacitors are each alternately and concurrently switched back and forth between the two signal paths for the two polarities of the input signal responsive to a clock signal in such a manner as to sample and integrate the input signal at an effective signal transfer rate of at least twice the clock frequency. An analog-to-digital converter defines a digital feedback-control signal characteristic of the integrator output signal. A second switched-capacitor arrangement selectively applies a feedback signal to the integrator inputs, responsive to the digital control signal, at a switching rate comparable to the effective signal transfer rate through the integrator.