초록 ▼

A method and spread spectrum transceiver for demodulating a spread spectrum signal is disclosed. A spread spectrum phase shift keyed (PSK) modulated information signal is received within a demodulator of a spread spectrum receiver on a signal channel. The information signal includes a sequence of da

A method and spread spectrum transceiver for demodulating a spread spectrum signal is disclosed. A spread spectrum phase shift keyed (PSK) modulated information signal is received within a demodulator of a spread spectrum receiver on a signal channel. The information signal includes a sequence of data symbols formed from a plurality of high rate mode chips. A precursor portion of the signal channel is Viterbi detected. A multi-state trellis is formed having a predetermined number of states. A post-cursor portion of the signal channel is feedback equalized with a finite impulse response filter having feedback taps operatively connected to a chip detection circuit that tracks high rate mode chips and a carrier loop circuit for phase and frequency tracking. The information signal is despread within a spread spectrum code function correlator.

대표청구항 ▼

A method and spread spectrum transceiver for demodulating a spread spectrum signal is disclosed. A spread spectrum phase shift keyed (PSK) modulated information signal is received within a demodulator of a spread spectrum receiver on a signal channel. The information signal includes a sequence of da

A method and spread spectrum transceiver for demodulating a spread spectrum signal is disclosed. A spread spectrum phase shift keyed (PSK) modulated information signal is received within a demodulator of a spread spectrum receiver on a signal channel. The information signal includes a sequence of data symbols formed from a plurality of high rate mode chips. A precursor portion of the signal channel is Viterbi detected. A multi-state trellis is formed having a predetermined number of states. A post-cursor portion of the signal channel is feedback equalized with a finite impulse response filter having feedback taps operatively connected to a chip detection circuit that tracks high rate mode chips and a carrier loop circuit for phase and frequency tracking. The information signal is despread within a spread spectrum code function correlator. sectional beam axis directions (x,y). 12. The laser system of claim 11, wherein a second resonator reflecting optic disperses the beam for narrowing a bandwidth of the beam. 13. The laser system of claim 11, wherein said at least one line-narrowing optic is disposed between said resonator reflecting surfaces. 14. The laser system of claim 11, wherein said first resonator reflecting optic disperses the beam for narrowing a bandwidth of the beam. 15. An excimer or molecular fluorine laser system, comprising: a laser chamber filled with a gas mixture at least including a halogen-containing molecular species and a buffer gas; a plurality of electrodes including a pair of main electrodes and at least one preionization unit within the laser chamber, the main electrodes defining a discharge area therebetween; a pulsed discharge circuit connected to the electrodes including a pulse compression circuit and a high voltage power supply for supplying electrical energy in compressed electrical pulses to the electrodes within the laser chamber to energize the gas mixture; a fan for circulating the gas mixture through the discharge area; a heat exchanger at least for cooling the gas mixture; a resonator for generating an output beam including the discharge area within the laser chamber and resonator reflecting optics at either end and retro-reflecting the beam within the resonator; a first intracavity optic for narrowing a bandwidth of the output beam and configured to magnify the beam in a first cross-sectional beam axis direction (x) and to render the resonator unstable in the first direction (x); and a second intracavity optic configured to magnify the beam in a second cross-sectional beam axis direction (x±θ) angularly offset from the first cross-sectional beam axis direction and to render the resonator unstable in the second direction (x±θ), said beam propagating within the resonator substantially in a third direction (z), and wherein the first and second intracavity optics thereby suppress fluctuations in one or more output beam parameters. 16. The laser system of claim 15, wherein said intracavity optics are configured to provide a magnification of the beam of at least 2 in each of said cross sectional beam axis directions (x,x±θ). 17. The laser system of claim 16, wherein said intracavity optics are configured to provide a magnification of the beam of not more than substantially 4 in each of said cross sectional beam axis directions (x,x±θ). 18. An excimer or molecular fluorine laser system, comprising: a laser chamber filled with a gas mixture at least including a halogen-containing molecular species and a buffer gas; a plurality of electrodes including a pair of main electrodes and at least one preionization unit within the laser chamber, the main electrodes defining a discharge area therebetween; a pulsed discharge circuit connected to the electrodes including a pulse compression circuit and a high voltage power supply for supplying electrical energy in compressed electrical pulses to the electrodes within the laser chamber to energize the gas mixture; a fan for circulating the gas mixture through the discharge area; a heat exchanger at least for cooling the gas mixture; a resonator for generating an output beam including the discharge area within the laser chamber and resonator reflecting surfaces at either end and retro-reflecting the beam within the resonator; at least one intracavity optic for narrowing a bandwidth of the output beam; a first intracavity optic configured to magnify the beam in a first cross-sectional beam axis direction (x) and to render the resonator unstable in the first direction (x); and a second intracavity optic configured to magnify the beam in a second cross-sectional beam axis direction (x±θ) angularly offset from the first cross-sectional beam axis direction and to render the resonator unstable in the second direction (x±θ), said beam propagating within the resona tor substantially in a third direction (z), and wherein the first and second intracavity optics thereby suppress fluctuations in one or more output beam parameters. 19. The laser system of claim 18, wherein said intracavity optics are configured to provide a magnification of the beam of at least 2 in each of said cross sectional beam axis directions (x,x±θ). 20. The laser system of claim 19, wherein said intracavity optics are configured to provide a magnification of the beam of not more than substantially 4 in each of said cross sectional beam axis directions (x,x±θ). 21. An excimer or molecular fluorine laser system, comprising: a laser chamber filled with a gas mixture at least including a halogen-containing molecular species and a buffer gas; a plurality of electrodes including a pair of main electrodes and at least one preionization unit within the laser chamber, the main electrodes defining a discharge area therebetween; a pulsed discharge circuit connected to the electrodes including a pulse compression circuit and a high voltage power supply for supplying electrical energy in compressed electrical pulses to the electrodes within the laser chamber to energize the gas mixture; a fan for circulating the gas mixture through the discharge area; a heat exchanger at least for cooling the gas mixture; a resonator for generating an output beam including the discharge area within the laser chamber and resonator reflecting surfaces at either end and retro-reflecting the beam within the resonator; an intracavity optic for narrowing a bandwidth of the output beam and configured to magnify the beam in a first and a second orthogonal cross-sectional beam axis directions (x,y) for suppressing fluctuations in one or more output beam parameters, said beam propagating within the resonator substantially in a third direction (z). 22. The laser system of claim 21, wherein said surface of said intracavity optical element is spherical. 23. The laser system of claim 21, wherein said surface of said intracavity optical element is toriqual. 24. The laser system of claim 21, wherein said intracavity optic is configured to provide a magnification of the beam of at least 2 in each of said orthogonal beam axis directions. 25. The laser system of claim 24, wherein said intracavity optic is configured to provide a magnification of the beam of not more than substantially 4 in each of said orthogonal beam axis directions. 26. An excimer or molecular fluorine laser system, comprising: a laser chamber filled with a gas mixture at least including a halogen-containing molecular species and a buffer gas; a plurality of electrodes including a pair of main electrodes and at least one preionization unit within the laser chamber, the main electrodes defining a discharge area therebetween; a pulsed discharge circuit connected to the electrodes including a pulse compression circuit and a high voltage power supply for supplying electrical energy in compressed electrical pulses to the electrodes within the laser chamber to energize the gas mixture; a fan for circulating the gas mixture through the discharge area; a heat exchanger at least for cooling the gas mixture; a resonator for generating an output beam including the discharge area within the laser chamber and resonator reflecting surfaces at either end and retro-reflecting the beam within the resonator; a first intracavity optic for narrowing a bandwidth of the output beam; and a second intracavity optic including a surface configured to magnify the beam in a first and a second orthogonal cross-sectional beam axis directions (x,y) for suppressing fluctuations in one or more output beam parameters, said beam propagating within the resonator substantially in a third direction (z). 27. The laser system of claim 26, wherein said surface of said second intracavity optical element is spherical. 28. The laser system of claim 26, wherein said surface of said second intracavity optical ele