摘要 |
<p>An ultra wide bandwidth, high speed, spread spectrum communications system uses short wavelets (103, 104) of electromagnetic energy to transmit information through objects such as walls or earth. The communication system uses baseband codes formed from time shifted and inverted wavelets (103, 104) to encode data on a RF signal. Typical wavelet pulse durations are on the order of 100 to 1000 picoseconds with a bandwidth of approximately 8 GHz to 1 GHz, respectively. The combination of short duration wavelets and encoding techniques are used to spread the signal energy over an ultra wide frequency band such that the energy is not concentrated in any particular energy band (e.g. VHF: 30-300MHz or UHF: 300-1000MHz) and is not detected by conventional narrow band receivers so it does not interfere with those communication systems.</p> |