The bandwidth demand for data transmission on copper cables increases more and more. For the characterization of such cables up to GHz frequencies it is advisable to use a vector network analyzer (VNA). However, the effort for its calibration can be considerable, since a star-quad cable consists of two twisted-pairs, which results in 128 calibration coefficients to be determined. It has previously been shown how to reduce the number of calibration coefficients significantly, by exploiting symmetry properties within a mixed-mode description of the measurement setup. As a part of that solution, four leaky 4-port error-networks must be calibrated. For this purpose, the present paper presents different novel 15-term self-calibration procedures, which finally result in a higher measurement accuracy. These procedures allow the calibration of 15-term error-networks without an ideal THRU- or LINE-connection. The first procedure named NMRG2 requires the same calibration standards as the well- known TMRG procedure, with the exception of the THRU, which can be replaced by a known network-standard. The second self-calibration procedure named MONS5 applies an unknown network, an asymmetric 2-port reflection and a match, whereas two other known reflection-standards are required.

The bandwidth demand for data transmission on copper cables increases more and more. For the characterisation of such cables up to GHz frequencies it is advisable to use a vector network analyzer (VNA). However, the effort for its calibration can be considerable, since a star-quad cable consists of two twisted-pairs, which results in 128 calibration coefficients to be determined. It has previously been shown [1] how to reduce the number of calibration coefficients significantly, by exploiting symmetry properties within a mixed-mode description of the measurement setup. As a part of that solution, four leaky 4-port error-networks must be calibrated. For this purpose, the present paper presents a novel combination of calibration standards to calibrate two 15-term error-networks in one step, the so called 31-term error-model. This procedure applies two network standards “N1” and “N2” to connect the two 15-term error-networks, a third network “N3” to connect both ports at the leaky error-networks and an asymmetric reflection standard “R”. The paper adresses the problem of MATCH-standards on non-metrology interfaces. They set the reference impedance, but have not a constant reflection for a bandwith of several GHz.

Recent trends in broadband access technology show the demand to extend the used frequency bands up to hundreds of MHz. Access cables are not built for such high frequencies, and measurements of access cables in this frequency range show a significant change of the cable characteristics compared to low frequencies. The novel modeling approach presented here is designed to be used for evaluation of transmission technologies for fiber-copper hybrid networks, so called FTTdp (Fiber To The distribution point), which enables service providers to serve customers with data rates in the GBit/s range without the requirement to install fiber to the home.

Increasing deployment of digital subscriber line (DSL) technology operating in the long wave, medium wave and sometimes short wave frequency ranges, has raised the question of how such systems interact with rival radio frequency sources and equipment. Two of the major standards bodies in the field, ITU and ETSI, imposed by the standardization of such promising technologies like ADSL, SHDSL and VDSL, have begun to elaborate performance tests for radio frequency interference (RFI) scenarios for inclusion into their standards documents. Existing out-door loops of the copper telephone network can have large dimensions, are often unshielded and sometimes not even twisted, thus, they can act like antennas for both RFI egress and ingress. The RFI egress issue requires basic knowledge of the relationship between a given current distribution I(l) on a twisted pair communication cable and the electromagnetic fleld E, H generated by that current distribution at a given distance d. This problem is reciprocal to the RFI ingress issue, which requires knowledge of the relationship between a disturbing high-frequency electric field E in the surroundings of a twisted pair cable, and the terminal voltage of that cable across a load impedance. This contribution provides the theoretical background to the field theoretical problem and supplies simple yet accurate approximation formulae for the prediction of RFI egress and RFI ingress.

We discuss the treatment of prevention statements in both natural language semantics and knowledge representation, with particular regard to existence entailments. First order representations with an explicit existence predicate are shown to not adequately capture the entailments of prevention statements. A linguistic analysis is framed in a higher order intensional logic, employing a Fregean notion of existence as instantiation of a concept. We discuss how this can be mapped to a Cyc style knowledge representation.