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US 4,901,148 AGranted
Data processing device
AssigneeCanon Kabushiki Kaisha
InventorsTadayoshi Nakayama, Chikara Satoh, Akio Fujii, Katsuji Yoshimura, Koji Takahashi
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Abstract
A data processing device having a memory which permits writing and reading of digital data and a digital-to-analog converter which converts digital data read out from the memory into an analog signal. The operating frequency of the converter obtained when the memory is solely performing data reading is arranged to be twice as high as the operating frequency of the converter obtained when the memory is performing both data writing and data reading.
Claims14
A data processing device comprising:
- (a) a first signal generating source arranged to generate a first information signal;
- (b) a second signal generating source arranged to generate a second information signal which has a greater amount of information per unit of time than said first information signal;
- (c) selecting means for selectively producing said first information signal or said second information signal;
- (d) analog-to-digital converting means for analog-to-digital converting signals produced by said selecting means;
- (e) storing means for storing signals digitized by said analog-to-digital converting means;
- and
- (f) change-over means for changing a sampling frequency of said analog-to-digital converting means and a data writing cycle of said storing means in response to a selecting action of said selecting means, such that the sampling frequency of said analog-to-digital converting means which is obtained while said selecting means is producing said first information signal and that of said analog-to-digital converting means which is obtained while said selecting means is producing said second information signal are caused to differ from each other in a ration of 1:n (wherein n represents an integer which is at least 2).
4 more elements
A data processing device comprising:
- (a) storing means arranged to permit reading of a digital signal stored therein;
- (b) digital-to-analog converting means for converting into an analog signal a digital signal read out from said storing means;
- (c) first and second output means;
- (d) selecting means for selectively supplying said analog signal produced from said digital-to-analog converting means either to said first output means or to said second output means;
- and
- (e) change-over means for changing an operating frequency of said digital-to-analog converting means from one frequency over to another and a data reading period of said storing means from one period over to another according to a selecting action of said selecting means.
3 more elements
A data processing device comprising:
- (a) storing means arranged to permit writing and reading of a digital signal into and from said storing means;
- (b) digital-to-analog converting means for converting into an analog signal a digital signal read out from said storing means;
- and
- (c) change-over means for switching said device between first and second modes, said device being arranged,
- in said first mode, to have said storing means perform writing and reading actions on a digital signal and to set an operating frequency of said digital-to-analog converting means at a first frequency and
- in said second mode, to have said storing means perform solely a reading action on a digital signal and to set the operating frequency of said digital-to-analog converting means at a second frequency which is twice as high as said first frequency.
3 more elements
Dependencies are inferred from the claim text.