| 摘要 |
A variable bandwidth filter device for use with a spread-spectrum transmitter including a chipping sequence generator, spread-spectrum processing means, an impulse generator, and a filter. The chipping-sequence generator generates a chipping sequence signal having a chipping-sequence-signal bandwidth. Using the chipping sequence signal, the spread-spectrum processing means processes a data signal to generate a spread-data signal having a spread bandwidth greater than the chipping-sequence-signal bandwidth. In response to each chip in the spread-data signal, the impulse generator generates an impulse signal. The filter filters the spectrum of each impulse signal with a bandpass equal to the spread bandwidth. The invention also comprises a method for generating a spread-spectrum signal using a chipping sequence having a rate less than the spread bandwidth. The method includes the steps of generating the chipping sequence, spread-spectrum processing a data signal with the chipping sequence, generating an impulse signal responsive to each chip, and filtering a spectrum of each impulse signal.
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