Patent ID: 8023558
Filing Date: 2011-09-20
Classification: G01R,H04B,H04L

Abstract:
1. A method of measuring a frequency response at a decision point of a digital receiver comprising the steps of: applying an input signal having an amplitude and a frequency to an input of the digital receiver; determining an amplitude of the input signal at the decision point by sampling the input signal at the decision point using a binary decision circuit while moving a decision threshold voltage of the binary decision circuit and measuring differences in the resulting decisions, an upper value of the amplitude of the input signal at the decision point being based on a minimum value of the decision threshold voltage for which every sample results in a decision that indicates that the input signal at the decision point is less than the decision threshold voltage, and a lower value of the amplitude of the input signal at the decision point being based on a maximum value of the decision threshold voltage for which every sample results in a decision that indicates that the input signal at the decision point is greater than the decision threshold voltage; and calculating the frequency response at the decision point as the ratio of the amplitude of the input signal at the decision point to the amplitude of the input signal at the input of the digital receiver.