Asynchronous analog-to-digital converter having adapative reference control

摘要

A method is provided. An analog signal is received. The analog input signal is compared to first and second reference signals to generate a first comparison result, and the first comparison result and a first time stamp corresponding to the first comparison result are registered. A first portion of a digital signal is generated from the first comparison result. At least one of the first and second reference signals is adjusted. A second comparison result is generated if the analog signal reaches an adjusted one of the first and second reference signals within a predetermined interval, and a second portion of the digital signal is generated from the second comparison result.

主权项

1. A method comprising:
receiving an analog signal; comparing the analog input signal to first and second reference signals to generate a first comparison result; registering the first comparison result and a first time stamp corresponding to the first comparison result; generating a first portion of a digital signal from the first comparison result; adjusting at least one of the first and second reference signals; generating a second comparison result if the analog signal reaches an adjusted one of the first and second reference signals within a predetermined interval; generating a second portion of the digital signal from the second comparison result, wherein the second reference signal is greater than the first reference signal, and wherein the method further comprises: if the analog signal becomes greater than the second reference signal, generating a third comparison result reflecting that the analog signal has become greater than the second reference signal; registering the third comparison result and a third time stamp corresponding to the third time comparison result; generating a third portion of a digital signal from the third comparison result; and generating a third reference signal that is greater than the second reference signal, wherein the method further comprises: if the analog signal becomes less than the first reference signal, generating a fourth comparison result reflecting that the analog signal has become less than the first reference signal; registering the fourth comparison result and a fourth time stamp corresponding to the fourth time comparison result; generating a fourth portion of a digital signal from the fourth comparison result; and generating a fourth reference signal that is less than the first reference signal, wherein the step of adjusting further comprises increasing the first reference signal, wherein the first reference signal is increase at a rate of an initial difference between the first and second reference signals divided by the length of the predetermined interval minus a blanking period.