Answering questions that may arise related to the meaning of portions of an IEEE standard concerning specific applications.

IEEE Standards Interpretation for IEEE Std 743™-1995 IEEE Standard Equipment Requirements and Measurement Techniques for Analog Transmission Parameters for Telecommunications

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20 August 2001

Interpretation Request #1
Topic: Clerical error in the tabulation of loss vs. frequency for the D Filter Relevant Clause: 9.1 D Filter Relevant Figure: Figure 17 Relevant Table: Table 30
In Figure 17 on page 83 of IEEE Std 743-1995, a tabulation of loss vs. frequency for the D Filter is given. At the bottom of page 85, a chart (Table 30) of pole/zero values for the same filter is given. The problem is that, in the 300-700 Hz Region, the loss calculated using the pole/zero data does not comply with the loss given in Table 30 in the third row in the column labeled "Z-plane poles."

Interpretation Response
There is an apparent clerical error in Table 30 of IEEE Std 743-1995. The source document specifying the digital poles and zeros, "Contribution IEEE P743/94-47," shows the components on the third lline of the "z-planes poles" column, to be 0.7258+/-j0.1629, and thus the real component number in the IEEE Std 743-1995 (0.7528) is apparently in error.