Title:
スペクトラム拡散クロック制御装置及びスペクトラム拡散クロック発生装置
Document Type and Number:
Japanese Patent JP4684919
Kind Code:
B2
Abstract:
Disclosed is an SSC controller that exercises control to supply a control signal to a phase interpolator which receives an input clock signal and varies the phase of an output clock signal in accordance with the control signal, and to frequency-modulate the output clock signal. In an SSC controller, a counting operation control circuit outputs a counting operation control signal that controls count enable and disable. A p-counter receives a frequency-divided clock signal from a frequency divider and counts the signal when the counting operation control signal from the counting operation control circuit indicates count enable. Upon counting up to a predetermined first value, the counting operation control circuit generates a first output signal and sets its count value to zero. When the counting operation control signal indicates count disable, the p-counter stops counting. An up/down counter receives the first output signal from the p-counter and counts this signal up and down between a predetermined initial value (=0) and a predetermined second value. On the basis of count values from the two counters, a controller outputs the phase control signal to the phase interpolator. The counting operation control circuit, which receives the count values from the two counters and is supplied with a control signal from an SSC control terminal, sets the counting operation control signal to a value indicative of count disable when the supplied control signal indicates count disable and both of the count values from the two counters are at their initial values (=0).
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Inventors:
Masao Nakahira
Application Number:
JP2006058304A
Publication Date:
May 18, 2011
Filing Date:
March 03, 2006
Export Citation:
Assignee:
Renesas Electronics Corporation
International Classes:
G06F1/04; G06F1/06; H03K23/00
Domestic Patent References:
| JP2005004451A | ||||
| JP2001160788A | ||||
| JP2001092311A | ||||
| JP2002073199A |
Attorney, Agent or Firm:
Kato Asamichi