Title:
【発明の名称】周波数合成雑音に対する疑似ランダム振動
Document Type and Number:
Japanese Patent JP2823913
Kind Code:
B2
Abstract:
A method and apparatus for reducing spurious output noise in digital frequency synthesizers employing sine amplitude converters connected to Digital-to-Analog converters to generate analog waveforms from sine amplitude data. Random or pseudorandom numbers having a value equal to or less than plus or minus one-half of a minimum quantization step or value change for the sine amplitude data are generated and added to the sine amplitude data with the resulting sum being transferred to the Digital-to-Analog converter. In one embodiment, a summation circuit is connected between an output of the sine function converter and an input of the Digital-to-Analog converter and also has a second input connected to a pseudorandom number generator which provides Pseudorandom numbers varying in value over a range of +/-1/2n+1 times a least significant step value, or bit for base 2, of a corresponding Digital-to-Analog input data value where n is greater than or equal to 1.
Inventors:
Kear, Richard Theei
Webber, Lindsay A
Webber, Lindsay A
Application Number:
JP50133489A
Publication Date:
November 11, 1998
Filing Date:
December 08, 1988
Export Citation:
Assignee:
Qualcomm, Inc.
International Classes:
G06F1/03; G06F3/05; G06J1/00; H03M1/04; H03B28/00; H03M1/08; H03M1/10; H03M1/66; (IPC1-7): H03M1/04; H03B28/00; H03M1/08
Domestic Patent References:
| JP62183627A | ||||
| JP58106901A | ||||
| JP5792925A | ||||
| JP61224573A | ||||
| JP5883402A |
Other References:
【文献】米国特許4652832(US,A)
Attorney, Agent or Firm:
Takehiko Suzue (3 outside)