Title:
CRYSTAL OSCILLATOR
Document Type and Number:
WIPO Patent Application WO/2005/046046
Kind Code:
A1
Abstract:
A crystal oscillator that exhibits an increased oscillator frequency variation amount in accordance with an externally supplied control voltage and that provides a frequency variation exhibiting an improved linearity. The crystal oscillator includes a frequency adjusting circuit configured by use of two MOS voltage variable capacitance elements. The back gate terminal of each MOS voltage variable capacitance element receives a control DC voltage via a respective one of level shift circuits. The voltage shift amount of one of the level shift circuits is established such that the corresponding MOS voltage variable capacitance element operates in a range where the C-V characteristic is linear in a range lower than the center voltage of the control DC voltage. The voltage shift amount of the other of the level shift circuits is established such that the corresponding MOS voltage variable capacitance element operates in a range where the C-V characteristic is linear in a range higher than the center voltage of the control DC voltage.
Inventors:
YAMAMOTO TAKEHIRO (JP)
Application Number:
PCT/JP2004/014964
Publication Date:
May 19, 2005
Filing Date:
October 08, 2004
Export Citation:
Assignee:
TOYO COMMUNICATION EQUIP (JP)
YAMAMOTO TAKEHIRO (JP)
YAMAMOTO TAKEHIRO (JP)
International Classes:
H03B5/04; H03B5/36; (IPC1-7): H03B5/32
Domestic Patent References:
| WO1996003799A1 | 1996-02-08 |
Foreign References:
| JPH1051238A | 1998-02-20 | |||
| JP2001352218A | 2001-12-21 | |||
| JP2000353918A | 2000-12-19 | |||
| JPH10303643A | 1998-11-13 | |||
| JP2002135051A | 2002-05-10 | |||
| JP2002043842A | 2002-02-08 | |||
| JPH0645826A | 1994-02-18 |
Attorney, Agent or Firm:
Suzuki, Hitoshi (28-1 Nakano 2-chom, Nakano-ku Tokyo 01, JP)
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