Title:
MODULATION METHOD AND SYSTEM
Document Type and Number:
Japanese Patent JP3323124
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide the modulation method and system where a carrier frequency is reduced without increasing the amount of arithmetic processing.
SOLUTION: A carrier shift section 12 shifts a frequency band of an output signal of a signal point generating section 11 by '-84 kHz'. An LPF 13 increases a sampling rate of an output signal of a carrier shift section 12 from 192 kHz to 768 kHz and limits the frequency band of the output signal of the carrier shift section 12 to a frequency band being a double width (384 kHz) of the modulation speed 192 kHz, including a base frequency band (width 192 kHz). A modulation section 14 shifts the frequency band of the output signal of the LPF 13 by 192 kHz that is 1/4 of the sampling frequency 786 kHz. The total shift amount is 108 kHz which is a carrier frequency to be outputted actually to a transmission line and the arithmetic operation is reduced.
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Inventors:
Hisashi Kaku
Hideo Miyazawa
Hideo Miyazawa
Application Number:
JP308898A
Publication Date:
September 09, 2002
Filing Date:
January 09, 1998
Export Citation:
Assignee:
富士通株式会社
International Classes:
H03D9/00; H03C3/00; H03K7/00; H04L27/00; (IPC1-7): H04L27/00
Domestic Patent References:
| JP7170301A |
Attorney, Agent or Firm:
Takashi Ishida (3 others)