| US 7,457,995 B1 | ||
| Method and apparatus for generating reference transmission signal for use in testing communications receivers | ||
| Benny Madsen, Los Altos, Calif. (US); Christian Olgaard, Sunnyvale, Calif. (US); Carsten Andersen, Sunnyvale, Calif. (US); Gary Wang, Milpitas, Calif. (US); Thomas Toldborg Andersen, Pleasanton, Calif. (US); and Peter Petersen, Concord, Calif. (US) | ||
| Assigned to LitePoint Corp., Sunnyvale, Calif. (US) | ||
| Filed on Feb. 02, 2004, as Appl. No. 10/769,971. | ||
| Int. Cl. G01R 31/28 (2006.01) | ||
| U.S. Cl. 714—712 [455/99] | 11 Claims |
| 1. A method for generating a reference transmission signal for use in testing a communications system, comprising:
capturing a data packet transmission signal containing a plurality of reference data;
digitizing said data packet transmission signal;
retrieving at least a selected portion of said plurality of reference data from said digitized data packet transmission signal
to produce a plurality of retrieved data;
modulating a carrier signal with said plurality of retrieved data to produce a digital transmission signal;
storing said digital transmission signal following said modulating of said carrier signal and prior to a use of said digital
transmission signal in producing said reference transmission signal for transmission and demodulation;
retrieving said stored digital transmission signal; and
quadrature frequency up-converting said retrieved digital transmission signal to produce said reference transmission signal.
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