Transmitting and receiving spread spectrum signals using continuous waveforms
View Patent ↗Systems and methods are described for transmitting and receiving spread spectrum signals using continuous waveforms. A method of transmitting a spread spectrum signal includes: generating a plurality of substantially continuous waveforms; summing the plurality of substantially continuous waveforms; modulating the summed plurality of substantially continuous waveforms to generate the spread spectrum signal; and transmitting the spread spectrum signal. A method of receiving a spread spectrum signal includes: generating a plurality of substantially continuous waveforms; summing the plurality of substantially continuous waveforms; modulating the summed plurality of substantially continuous waveforms with a code; mixing the modulated summed plurality of substantially continuous waveforms with the spread spectrum signal to produce a baseband signal; integrating the baseband signal; and detecting data.
1. An apparatus, comprising a spread spectrum transmitter including:
a comb generator, wherein the comb generator is operable to generate a plurality of harmonics;
a summing node coupled to the comb generator;
a modulator coupled to the summing node and operable to modulate a first one or more of the plurality of harmonics such that a transmitted signal substantially conforms to a first PSD profile during a first time period and modulate a second one or more of the plurality of harmonics such that a transmitted signal substantially conforms to a second PSD profile in a second time period, wherein the PSD of the transmitted signal during the first time period is the result of the modulation of the first one or more of the plurality of harmonics and the PSD of the transmitted signal during the second time period is the result of the modulation of the second one or more of the plurality of harmonics, the first one or more of the plurality of harmonics is determined based on the first PSD profile, the second one or more of the plurality of harmonics is determined based on the second PSD profile and the first one or more of the plurality of harmonics is different than the second one or more of the plurality of harmonics;
a spread spectrum signal output coupled to the modulator;
a data encoder coupled to the modulator;
a data input coupled to the data encoder;
a code source coupled to the data encoder; and
a clock coupled to both the data encoder and the comb generator, such that both the data encoder and the comb generator share a common frequency reference.
2. The apparatus of claim 1 , further comprising a plurality of harmonically related phase lock loop circuits coupled to the summing node, wherein each of the harmonically related phase lock loop circuits is coupled to the comb generator.
3. An ultra wideband router comprising the apparatus of claim 1 .
4. An apparatus, comprising a spread spectrum signal receiver including:
a comb generator, wherein the comb generator is operable to generate a plurality of harmonics;
a summing node coupled to the comb generator;
a modulator coupled to the summing node and operable to modulate a first set of the plurality of harmonics such that a transmitted signal substantially conforms to a first PSD profile during a first time period and modulate a second set of the plurality of harmonics such that a transmitted signal substantially conforms to a second PSD profile in a second time period wherein the PSD of the transmitted signal during the first time period is the result of the modulation of the first set of the plurality of harmonics and the PSD of the transmitted signal during the second time period is the result of the modulation of the second set of the plurality of harmonics, the first set of the plurality of harmonics is determined based on the first PSD profile, the second set of the plurality of harmonics is determined based on the second PSD profile and the first set of the plurality of harmonics is different than the second set of the plurality of harmonics;
a code source circuit coupled to the modulator;
a clock coupled to both the code source circuit and the comb generator, such that both a data encoder and the comb generator share a common frequency reference;
a multiplier coupled to the modulator;
a spread spectrum signal input coupled to the multiplier;
an integration circuit coupled to the multiplier; and
a data output coupled to the integration circuit.
5. The apparatus of claim 4 , further comprising a plurality of harmonically related phase lock loop circuits coupled to the summing node, wherein each of the harmonically related phase lock loop circuits is coupled to the comb generator.
6. The apparatus of claim 4 , wherein the multiplier includes a mixer.
7. An ultra wideband router comprising the apparatus of claim 4 .
8. A method for transmitting a spread spectrum signal, including:
generating a plurality of harmonics of a reference clock via a comb generator, wherein the plurality of harmonics are synchronized with the reference clock;
selecting a first set of the harmonics based on a first power spectral density (PSD) profile;
selecting a second set of the harmonics based on a second power spectral density (PSD) profile, wherein the first set of the plurality of harmonics is different than the second set of the plurality of harmonics;
modulating the selected first set of harmonics with data during a first time period to generate a first spread spectrum signal such that the first spread spectrum signal conforms to the first PSD profile during the first time period, wherein the PSD of the first spread spectrum signal is the result of the modulation of the selected first set of harmonics;
transmitting the first spread spectrum signal;
modulating the selected second set of harmonics with data during a second time period to generate a second spread spectrum signal such that the second spread spectrum signal conforms to the second PSD profile during the second time period, wherein the PSD of the second spread spectrum signal is the result of the modulation of the selected second set of harmonics; and
transmitting the second spread spectrum signal.
9. The method of claim 8 , wherein the first PSD has an amplitude profile mask.
10. The method of claim 8 , further comprising detecting a wireless device, wherein the first PSD profile is selected to avoid interference in a band corresponding to a signal transmitted by the wireless device.
11. The method of claim 10 , wherein the signal of the wireless device has a first phase and a phase of one or more of the set of harmonics is selected based on the phase of the signal transmitted by the wireless device.
12. An apparatus for transmitting a spread spectrum signal, comprising:
a reference clock operable to generate a reference signal;
a harmonic comb generator operable to generate a plurality of harmonics of the reference clock which are synchronous with the reference clock;
logic operable to select a first set of harmonics based on a first power spectral density (PSD) profile and a second set of harmonics based on a second PSD profile, wherein the first set of harmonics is different than the second set of harmonics;
a mixer operable to modulate the first set of harmonics with a data signal to generate a spread spectrum signal which substantially conforms to the first power spectral density (PSD) profile during a first time period, wherein the spread spectrum signal substantially conforms to the first PSD profile during the first time period as result of the modulation of the first set of harmonics, and modulate the second set of the plurality of harmonics with the data signal to generate the spread spectrum signal which substantially conforms to the second PSD profile during a second time period, wherein the spread spectrum signal substantially conforms to the second PSD profile during the second time period as a result of the modulation of the second set of harmonics; and
an antenna operable to transmit the spread spectrum signal.
13. The apparatus of claim 12 , wherein the first PSD profile has an amplitude profile mask.
14. The apparatus of claim 12 , wherein the logic is operable to detect a wireless device, wherein the first PSD profile is selected to avoid interference in a band corresponding to a signal transmitted by the wireless device.
15. The apparatus of claim 14 , wherein the signal of the wireless device has a first phase and a phase of one or more of the set of harmonics is selected based on the phase of the signal transmitted by the wireless device.
16. The method of claim 8 , further comprising:
generating a plurality of substantially continuous waveforms via a comb generator;
synchronizing each of the plurality of substantially continuous waveforms to one of a plurality of phase lock loops wherein the plurality of phase lock loops are based on a common frequency reference;
summing the plurality of substantially continuous waveforms;
modulating the summed plurality of substantially continuous waveforms with a code;
mixing the modulated summed plurality of substantially continuous waveforms with the spread spectrum signal to produce a baseband signal;
integrating the baseband signal;
detecting data corresponding to the baseband signal; and
outputting the detected data.
17. The method of claim 16 , further comprising adaptively adjusting a phase of each of the plurality of substantially continuous waveforms, wherein the plurality of substantially continuous waveforms are harmonically related.
18. The method of claim 17 , further comprising adaptively adjusting an amplitude of each of the plurality of substantially continuous waveforms, wherein the plurality of substantially continuous waveforms are harmonically related.
19. The method of claim 16 , further comprising adaptively adjusting an amplitude of each of the plurality of substantially continuous waveforms, wherein the plurality of substantially continuous waveforms are harmonically related.
20. The method of claim 16 , wherein the spread spectrum signal includes an ultra wideband signal.
21. The apparatus of claim 1 , wherein the modulator is operable to modulate each of the first one or more of the plurality of harmonics differently from one another during the first time period such that the transmitted signal substantially conforms to the first PSD profile during the first time period and modulate each of the second one or more of the plurality of harmonics differently from one another during the second time period such that the transmitted signal substantially conforms to the second PSD profile during the second time period.
22. The method of claim 8 , wherein each of the first one or more of the plurality of harmonics is modulated differently from one another during the first time period such that the transmitted signal substantially conforms to the first PSD profile during the first time period and each of the second one or more of the plurality of harmonics is modulated differently from one another during the second time period such that the transmitted signal substantially conforms to the second PSD profile during the second time period.