Waveform analyzer

A method of determining a voltage of a signal at a particular point in time, the method comprising:

• receiving the signal;
• generating a threshold that varies from a first voltage to a second voltage, the first voltage being less than a minimum voltage expected to be exhibited by the received signal, the second voltage being greater than the maximum voltage expected to be exhibited by the received signal, and the variation of the threshold exhibiting a slope greater than a greatest slope expected to be exhibited by the received signal;
• and
• comparing the received signal to the threshold, to determine a point in time at which the received signal exceeds the varied threshold.

A method of determining whether a symbol is aberrant, the method comprising:

• receiving the symbol;
• determining, whether the symbol exhibits a voltage greater than a first voltage level at a first point in time relative to a the symbol;
• determining, whether the symbol exhibits a voltage less than a second voltage level at a second point in time relative to a the symbol;
• and
• deciding that the symbol is aberrant, based upon the determination steps.

A method of determining a maximum intersymbol interference exerted upon any symbol within a signal that has been acted upon by a system, the method comprising:

• determining a length of a step response exhibited by the system;
• determining a shape of the step response;
• and
• determining the maximum intersymbol interference based upon the length and shape of the step response.

A method of determining standard deviation of a region of a probability density function presumed to be gaussian describing jitter or amplitude noise of a signal, the method comprising:

• determining a first probability that a feature of the signal exhibits a magnitude greater than or equal to a first chosen value;
• determining a second probability that the feature of the signal exhibits a magnitude greater than or equal to a second chosen value;
• adding a known quantity of noise to the signal, yielding a noise-enhanced signal;
• determining a first magnitude of the feature, such that the noise-enhanced signal exhibits a probability of exhibiting the feature with a magnitude greater than or equal to the first magnitude equal to the first probability;
• determining a second magnitude of the feature, such that the noise-enhanced signal exhibits a probability of exhibiting the feature with a magnitude greater than or equal to the second magnitude equal to the second probability;
• and
• determining the standard deviation of the signal, based upon the known quantity of noise, first and second chosen values, and first and second magnitudes.