Description: The calibrated echo response UER(i* f), shall be represented in linear format by a scale factor and a normalized complex number a(i)+j*b(i), where i is the subcarrier index i ranging from 0 to NSC-1 and Df = 4.3125kHz and (NSC-1) * Df is the highest frequency supported by the SELT-PMD functionality. The scale factor shall be coded as a 16 bit unsigned integer. Both a(i) and b(i) shall be coded as a 16 bit 2's complement signed integer. The value of UER(i* f) shall be defined as UER(i* f) = (scale/215)*(a(i)+j*b(i))/215. In order to maximize precision, the scale factor shall be chosen such that max(|a(i)|, |b(i)|) over all i is equal to 215-1. This data format supports an UER(f) granularity of 2-15 and an UER(f) dynamic range of approximately +6 dB to -90 dB. An UER(i*Df) value indicated as a(i) = b(i) = -215 is a special value. It indicates that no measurement could be done for this subcarrier because it is out of the PSD mask passband or that the value is out of range to be represented.