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AssigneeBell Telephone Laboratories, Incorporated
InventorsDavid L. Favin, Peter F. Lynn, Paul J. Snyder
Estimating the term…
Accurate and reliable measurement results are obtained in a test system (FIG. 1) employing digital data acquisition units (121) when measuring frequency response or envelope delay distortion of a network or communication facility (105) by employing a unique test signal (21-tone) including a plurality of tones, each tone having amplitude, frequency, phase component values determined and assigned in accordance with prescribed criteria. The phase component values are determined in accordance with a relationship dependent on the number of tones in the test signal, and in one example, are initially assigned on a random, one-to-one basis to the tones. In a specific embodiment, a test signal is utilized having 21 tones. Further problems arising from nonlinearities on the facility under evaluation (105) are minimized by transmitting the 21-tone test signal a plurality of times and by reassigning the phase component values to the tones each time the test signal is transmitted. In a specific example, the phase component values are reassigned to the tones in counterclockwise, circular fashion after each transmission of the test signal until each tone has taken on each phase component value. Once measurements, i.e., data records, of the transmitted test signal have been obtained, they are utilized to obtain a spectrum, and in turn, the frequency components of the spectrum are employed to obtain the desired measurement of frequency response or envelope delay distortion.
Apparatus (FIG. 1) for obtaining a measure of at least one prescribed transmission characteristic of a network or facility (105) of the type including the generation and transmission of a test signal having a plurality of tones over the network or facility and utilizing characteristics of a received version of the transmitted test signal to generate the measure of the at least one prescribed transmission characteristic, wherein the improvement comprises,
Apparatus adapted for use in measuring at least one prescribed transmission characteristic of a network or facility of the type including
Apparatus (FIG. 1) for obtaining a measure of at least one prescribed transmission characteristic of a network, or facility (105) of the type including,
A method for generating a measurement of at least one prescribed transmission characteristic of a network or facility under evaluation comprising the steps of,
Dependencies are inferred from the claim text.