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Patent Searching and Data


Title:
FREQUENCY MODULATION CIRCUIT, TRANSMITTER, AND COMMUNICATION APPARATUS
Document Type and Number:
Japanese Patent JP2008054301
Kind Code:
A
Abstract:

To provide a frequency modulation circuit which reduces noise present in a frequency band which requires low noise, and operates with low distortion, high efficiency and low noise.

A bandpass type delta sigma modulation section 15 performs delta sigma modulation on an inputted modulation signal such that quantization noise is reduced in a frequency band which requires low noise. An LPF 16 removes a noise component in a high frequency region from the signal on which the delta sigma modulation has been performed. A frequency modulation circuit 1 reduces noise in the frequency band which requires low noise with the bandpass type delta sigma modulation section 15 and the LPF 16, and reduces noise in the vicinity of a direct current component DC with a feedback comparison section 11 and a loop filter 12.


Inventors:
MATSUURA TORU
Application Number:
JP2007188506A
Publication Date:
March 06, 2008
Filing Date:
July 19, 2007
Export Citation:
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Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
H03C3/08; H04B1/04
Attorney, Agent or Firm:
Shiro Ogasawara