Title:
FREQUENCY-VARIABLE FILTER
Document Type and Number:
WIPO Patent Application WO/2011/117911
Kind Code:
A1
Abstract:
A frequency-variable filter has a GmC filter and a pseudo-random value generator, wherein the GmC filter has an input-side OTA for converting an input voltage of an input terminal to a current, a capacitor for generating an output voltage to an output terminal on the basis of an output current of the input-side OTA, and a feedback-side OTA provided between the output terminal and the input-side OTA, and has a cut-off frequency corresponding to the transconductance and the capacity value of the capacitor. Furthermore, a pseudo-random value generator generates pseudo-random values corresponding to an input setting value at a high frequency, and the average value within a predetermined amount of time of the pseudo-random values is taken as a value corresponding to the input setting value. In addition, for at least the feedback-side OTA, the transconductance is variably controlled according to the pseudo-random values, and the cut-off frequency is variably controlled on the basis of the input setting value.
Inventors:
OISHI KAZUAKI (JP)
Application Number:
PCT/JP2010/002025
Publication Date:
September 29, 2011
Filing Date:
March 23, 2010
Export Citation:
Assignee:
FUJITSU LTD (JP)
OISHI KAZUAKI (JP)
OISHI KAZUAKI (JP)
International Classes:
H03H11/04; H04B1/26
Domestic Patent References:
| WO2007058012A1 | 2007-05-24 |
Foreign References:
| JP2002359543A | 2002-12-13 | |||
| US20050179505A1 | 2005-08-18 | |||
| JP2008085454A | 2008-04-10 |
Attorney, Agent or Firm:
DOI, Kenji et al. (JP)
Kenji Doi (JP)
Kenji Doi (JP)
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Claims: