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4395A NA - Transfer Function Differences in measurements

Question asked by edertp on Mar 22, 2006
Latest reply on Mar 24, 2006 by mmule54
Hi everybody, before a post i searched the best forum to ask and i think this is the right, if not forgive me and please indicate other.

I’m using a "4395A Network Analyzer" from Agilent to measure the transfer function in order to make comparisons in xDSL systems. In this way, i measured the transfers functions from a real cable with 10 pairs, 1.400 m length and 0.4 mm gauge and two different wireline simulators (ADSL and ADSL2++ from Spirent) simulating this real cable. So, i noticed the transfer function (Hf) from the real cable is always lower ( i mean +- 1dB for lowers frequencies and up to 10dB to upper frequency) than the wireline simulator, when they are compared to each frequency tone. That's something at least strange, because i already performed the measurements 4 for times. My question is if you (i hope at least one ) already heart something about this? Or even have any idea to explain this difference between real measurements and simulated ones.

Just to make you know i used the ADSL frequency: 4.3125kHz up to 1.104MHz

Sure there are many configurations i didn't show here, but just ask it.

Thanks a lot since now.