Title:
ベースバンド雑音を変調し、雑音の折り返しを低減する信号処理システム
Document Type and Number:
Japanese Patent JP2006516377
Kind Code:
A
Abstract:
A digital-to-analog converter ("DAC") system utilizes chopping modulation technology to remove 1/f and other baseband noise from a baseband of a signal of interest. Chopping modulation and demodulation circuitry of the DAC operate at a chopping frequency equal to approximately one-half of a digital input signal sampling frequency. Chopping at one-half the sampling frequency allows fold back into the baseband of the input signal's frequency components and reduces fold back of noise, such as quantization noise, residing outside the baseband. In a further embodiment, a notch filter attenuates signals having frequencies around the chopping frequency prior to chopping to reduce fold back of noise into the baseband due to parasitic modulation. Coordination of chopping timing also reduces noises in the output of the DAC system.
Inventors:
Presh, Marjorie Earl.
Mellanson, John El.
Hodup, Stephan Tea.
Langan, Gili N. K..
Mellanson, John El.
Hodup, Stephan Tea.
Langan, Gili N. K..
Application Number:
JP2006501064A
Publication Date:
June 29, 2006
Filing Date:
January 21, 2004
Export Citation:
Assignee:
Cirrus Logic,Inc.
International Classes:
H03M3/02; H03F1/02; H03F1/26; H03F3/21; H03F3/217; H03F3/38; H03M3/04
Attorney, Agent or Firm:
Hidesaku Yamamoto
Takaaki Yasumura
Natsuki Morishita
Takaaki Yasumura
Natsuki Morishita
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