SymClk Err (DOCSIS 4.0 Upstream)

SymClk Err is the symbol clock frequency error, which is the difference between the ideal and actual symbol clock frequency (in ppm). A symbol clock frequency that is less than ideal will cause the OFDM symbol time to take longer than required resulting in a decreased OFDM subcarrier spacing. A symbol clock frequency that is greater than ideal will cause the symbol times to take less time than required resulting in an increased OFDM subcarrier spacing. In either case this creates subcarrier interference and increases the signal's EVM. The resultant error value is a unitless fraction, which is multiplied by 1,000,000 to obtain SymClkErr in ppm.