| 摘要 |
New packet data devices operate within a first frequency band, while old version devices operate within a second frequency band. The first frequency band differs from, but overlaps with, the second frequency band. The new devices operate on a first carrier frequency (within the first frequency band) while old devices operate at a second carrier frequency (within the second frequency band). Preamble, header, and trailer portions of the new signal include a plurality of spectral copies of a baseband signal. One or more of these spectral copies of the baseband modulated signal is indistinguishable from corresponding components of an old version signal. The payload of the new version signal may be formed in the same manner, or may be formed in have a wider bandwidth, higher data rate format. |
