| Thread Links | Date Links | ||||
|---|---|---|---|---|---|
| Thread Prev | Thread Next | Thread Index | Date Prev | Date Next | Date Index |
|
All – We have looked at the S4P data provided from the June 1 ad hoc, which has a suckout between 7 GHz and 8 GHz. The resulting impulse responses confirm what we discussed on the call, namely that both the echo response and the insertion loss
impulse response have an oscillation that carries on for a long time, but that the oscillation is a) at a high frequency (so it would be attenuated by the reduced out-of-band transmit energy and a receive filter) and b) contains very little energy (sufficient
to allow 20-30dB SNRs if left as an uncancelled/unequalized tail). There are still concerns about other effects, such as timing recovery, but those will have to wait for later definition of modulation and signal processing structures. Additionally, such suckouts are often related to EM emissions and EM
susceptibility, and may be expected to increase reflections where multiple cables are connected (e.g., by inliners) into a single link segment. These concerns might looked at better by cabling experts. Normal practice is to limit such suckouts to 25% outside Nyquist, which allows some room for filtering to attenuate any effects. While it appears we might relax that limit a little, I’d leave that analysis for a later day when we know
more about the actual modulation and signal processing. Regardless, it doesn’t look like Echo response or basic equalization are impaired substantially. George Zimmerman, Ph.D. President & Principal CME Consulting, Inc. Experts in Advanced PHYsical Communications 310-920-3860 To unsubscribe from the STDS-802-3-B10GAUTO list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-B10GAUTO&A=1 |