Method of generating a clock, a clock generation device, and electronic apparatuses having a clock generation device
AssigneeRohm Co., Ltd.
InventorMasayu Fujiwara
Life of this patent
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Abstract
In generating a frequency-modulated clock, a first frequency modulation (FM) signal having frequency fm1 is frequency-modulated by a second FM signal having a second frequency fm2, generating a clock modulation signal fm0. The clock generation signal fm0 is used to frequency-modulate the system clock CLK by the clock modulation signal fm0. Thus, the spectrum of the clock is doubly dispersed by the first and the second FM frequencies. As a result, peak levels at the fundamental and higher harmonic frequencies are reduced as compared with conventional clock generation device.
Claims18
A method of generating a clock, comprising steps of:
- frequency-modulating a first signal having a first frequency by a second signal having a second frequency to generate a clock modulation signal;
- and
- frequency modulating said clock by said clock modulation signal to thereby generate a doubly frequency-modulated clock in a predetermined range.
A clock generation device, comprising:
- a clock generator for generating a clock having a predetermined frequency, said clock generator adapted to receive a frequency modulation (FM) signal;
- a modulation signal generator for generating a clock modulation signal by generating a first and a second FM signals having a first and a second frequencies, respectively, and by frequency-modulating said first FM signal by said second FM signal, wherein
- said clock modulation signal is supplied to said clock generator to thereby frequency-modulate said clock to generate a doubly frequency-modulated clock having a range of frequencies.
An electronic apparatus having a clock generation device which includes
- a clock generator for generating a clock having a predetermined frequency, said clock generator adapted to receive a frequency modulation (FM) signal;
- a modulation signal generator for generating a clock modulation signal by generating a first and a second FM signals having a first and a second frequencies, respectively, and by frequency-modulating said first FM signal by said second FM signal, wherein
- said clock modulation signal is supplied to said clock generator to thereby frequency-modulate said clock to generate a doubly frequency-modulated clock which has a range of frequencies not affecting the operations of said electronic apparatus and serves as a time base of said electronic apparatus.
Dependencies are inferred from the claim text.