Method and apparatus for performance metric compatible control of data transmission signals

A hardware apparatus for determining a non-normal signal level for a symbol which produces a non-normal symbol-error-rate in a data transmission system, the apparatus comprising:

• a receiver;
• a DC offset circuit which receives a differential input signal, wherein the differential input signal encodes the symbol, and wherein a differential output signal of the DC offset circuit is provided as input to the receiver;
• and
• circuitry to determine the non-normal signal level for the symbol by using the DC offset circuit to change a DC offset of each signal in the differential input signal by a different amount so that a symbol-error-rate measured by the receiver is substantially equal to the non-normal symbol-error-rate.

A computer-based system for determining a non-normal signal level for a symbol which produces a non-normal symbol-error-rate in a data transmission system, the computer-based system comprising:

• a receiver;
• a DC offset circuit which receives a differential input signal, wherein the differential input signal encodes the symbol, and wherein a differential output signal of the DC offset circuit is provided as input to the receiver;
• a processor;
• and
• a non-transitory computer-readable storage medium storing instructions that when executed by the processor cause the computer-based system to determine the non-normal signal level for the symbol by using the DC offset circuit to change a DC offset of each signal in the differential input signal by a different amount so that a symbol-error-rate measured by the receiver is substantially equal to the non-normal symbol-error-rate.