METHOD FOR SUPPRESSING SPUR INTERFERENCE IN MULTI-SUB-CHANNEL RECEIVERS USING FREQUENCY-INTERPOLATED PILOTS
Original Publication Date: 1995-Nov-01
Included in the Prior Art Database: 2002-Apr-08
Portable computing devices such as notebook computers, personal digital assistants (PDA), and the like produce electromagnetic interference (EMI). These emissions are due to internal electrical sig- nals such as clocks, data busses, and control lines changing state and radiating. These signals which are radiated can have spectra1 components which may interfere in frequency bands used for data trans- mission. The following method provides a means to suppress the effects of narrow-band emissions or spurs for receivers of multi-subchannel modulation sys- terns employing time and frequency interpolated pilots (a form of Pilot Symbol Assisted Modulation or PSAM) as a means of carrier recovery. These receivers may act as a peripheral device to such port- able computing equipment and thus be subject to spur interference. In most cases, the compactness dictated by the portable computer market forces the receive antenna to be physically close to the com- puter, compounding the spur interference problem.