Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Electrical signal parameter measurement system
Reexamination Certificate
1998-12-23
2001-07-17
Assouad, Patrick (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Electrical signal parameter measurement system
C702S191000, C455S423000
Reexamination Certificate
active
06263289
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of enhancing the dynamic range of intermodulation distortion measurements.
Intermodulation distortion (IMD), especially in the form of adjacent-channel power ratio (ACPR), is an important specification for cellular base stations, especially for the power amplifier. Suppliers must demonstrate that they meet these specifications.
The specifications for some of the newer communications formats, such as many forms of wideband CDMA and for multi-carrier base stations, dictate levels of ACP that seriously challenge the ability of test equipment to perform the measurement. Similar considerations apply to measuring other parameters that quantize intermodulation distortion effects, including multi-tone methods and noise power ratio.
The present invention provides a technique for measuring ACP and other forms of IMD of amplifiers and other two-port devices. The technique, which uses standard equipment, enhances the traditional dynamic range of measurement by at least 25 dB.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method of enhancing the dynamic range of intermodulation distortion measurements.
In one preferred embodiment, the present invention provides a method of enhancing the dynamic range of intermodulation distortion measurements comprising the steps of:
applying a signal source over a first path to a device under test (DUT);
measuring with a measuring instrument through a power combiner the signal power out of the DUT to form a reference power, which sometimes includes and sometimes doe not include measuring any spectral power components of IMD such as adjacent-channel power introduced the DUT, the signal source and the measuring instrument;
applying a cancellation signal over a second path and the power combiner to the measuring instrument that substantially cancels the signal over the first path through level and phase conditioning components and the power combiner to remove substantially most of the main channel power introduced from the DUT and substantially most of spectral power components of IMD such as adjacent-channel power introduced by the signal source and amplified by the DUT, and;
measuring the DUT introduced spectral components of IMD (intermodulation distortion) such as adjacent-channel power to enhance the dynamic range measurement.
REFERENCES:
patent: 3032712 (1962-05-01), Hurvitz
patent: 5160895 (1992-11-01), Siddoway et al.
patent: 5239683 (1993-08-01), Usui
patent: 5818240 (1998-10-01), Cabot
patent: 6097324 (2000-08-01), Myer et al.
Hassun Roland
Kuhn Nicholas J
Agilent Technologie,s Inc.
Assouad Patrick
Barbee Manuel L.
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