ZyXEL Communications IES-6000 manual IES-5000/5005/6000 Support Notes Impulse Noise Protection INP

IES-5000/5005/6000 Support Notes

Impulse Noise Protection (INP)

The impulse noise generator is required to prove the burst noise immunity of the VDSL transceiver. The noise shall consist of bursts of additive white Gaussian noise (AWGN) injected onto the line with sufficient power to ensure effective erasure of the data for the period of the burst, i.e., the bit error ratio during the burst shall be approximately 0.5 (assuming FEC is not applied). The noise burst shall be applied regularly at a repetition rate of at least 1 Hz. The duration of the burst is variable; at least values of 10, 50, 100, 250, and 500 μs shall be supported. The AWGN shall be generated with crest-factor of 5 and flat PSD up to 12 MHz, and further continuously declined with a roll-off equal to or steeper than 12 dB per octave. The PSD of the AWGN shall be variable in the range from –70 dBm/Hz to –140 dBm/Hz.

Interleaving shall be used to protect the data against bursts of errors by spreading the errors over a number of Reed-Solomon codewords. Interleaving can be programmable by software. Sudden strike noise can cause packet error. A buffer to protect ADSL Physical connection.

Error ratio during the burst shall be approximately 0.5 (assuming FEC is not applied). The noise burst shall be applied regularly at a repetition rate of at least 1 Hz. The duration of the burst is variable; at least values of 10, 50, 100, 250, and 500 μs shall be supported. The AWGN shall be generated with crest-factor of 5 and flat PSD up to 12 MHz, and further continuously declined with a roll-off equal to or steeper than 12 dB per octave. The PSD of the AWGN shall be variable in the range from –70 dBm/Hz to –140 dBm/Hz.

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