Method and apparatus for identifying a drift in a quantized signal in a computer system

A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for identifying a drift in a signal in a computer system, the method comprising:

• receiving a sequence of quantized signal values of the signal;
• generating a statistical distribution based on the sequence of quantized signal values, wherein the statistical distribution is generated using a set of counters, wherein each counter keeps track of the number of occurrences of an associated quantized signal value;
• if the sum of the set of counters is greater than or equal to a threshold, adjusting the counters by multiplying each counter in the set of counters by a compression factor;
• and
• identifying the drift in the signal by comparing the statistical distribution with a reference statistical distribution of the quantized signal values, wherein the reference statistical distribution is generated by computing the mean and variance of the quantized signal values received over a predetermined time period during normal operation of the computer system.

An apparatus for identifying a drift in a signal in a computer system, comprising:

• a receiving mechanism configured to receive a sequence of quantized signal values of the signal;
• a generating mechanism configured to generate a statistical distribution based on the sequence of quantized signal values, wherein the statistical distribution is generated using a set of counters, wherein each counter keeps track of the number of occurrences of an associated quantized signal value;
• an adjusting mechanism, wherein if the sum of the set of counters is greater than or equal to a threshold, the adjusting mechanism is configured to adjust the counters by multiplying each counter in the set of counters by a compression factor;
• and
• an identifying mechanism configured to identify the drift in the signal by comparing the statistical distribution with a reference statistical distribution of the quantized signal values, wherein the reference statistical distribution is generated by computing the mean and variance of the quantized signal values received over a predetermined time period during normal operation of the computer system.