US 5,122,800 A · Variable successive approximation converter

Abstract

Analog electrical signals are converted to digital form by analog to digital sampling in accordance with a variable successive approximation technique that permits extremely wide dynamic range coupled simultaneously with extremely high bandwidth capabilities, low power consumption, and low cost. Each of multiple data (sample) points of the input analog signal are digitally compared to a variable reference generated according to the successive approximation process and changeable modes of that process so as to permit optimum efficiency of conversion at varying rates of acquisition of the input signal. Variable conversion resolutions, gain, and offset settings are offered without resort to amplifiers, AC coupling, or settable attenuators, and applications for this conversion circuitry and method are described including oscillography, time-domain reflectometry, device and network characterization, telephony, video systems, data logging, equipment self-testing, device and process monitoring and control, spectrum analysis, and logic analysis.

Claims20

Dependent claims

A method of cenverting an analog input signal to digital form, comprising the steps of:

a first step of comparing the analog input signal with a first analog compare level to generate a digital signal indicative of the comparison result;
at least one succeeding step of comparing the input signal again with a subsequent analog compare level, wherein the subsequent analog compare level is changed to either higher or lower in amplitude than the proceding analog compare level in the prior step depending on the digital signal of the prior comparison result, and wherein the change in the analog compare level is effected so as to converge on the input signal level, and the defference between successive analog compare levels is of a known magnitude;
said analog compare levels having variable range for accommodating different analog input signals;
and
storing either the digital results of the comparison between the analog inout signal and each of the analog compare signals, or storing a final digital representation of the analog input signal determined from the succession of comparisons and changes of the analog compare valve.

2 more elements

Dependencies are inferred from the claim text.

Variable successive approximation converter

Life of this patent

Variable successive approximation converter

Life of this patent

Abstract

Claims20