Shared parallel digital-to-analog conversion
First Claim
1. A machine used for digital-to-analog conversion, comprising:
- a. a first counter which provides a first count b. a first analog reference source which provides a first analog reference signal c. a first digital number value to be converted to a first analog value d. means for causing said first count to change as a function of time e. means for causing said first analog reference signal to change as a function of time f. means for detecting when said first count reaches said first digital number value g. means for recording the value of said first analog reference signal as said first analog value when said first count reaches said first digital number value whereby said first analog value is the converted value of said first digital number value.
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Abstract
A machine used for conversion of digital number values to analog signal values. In one embodiment, a counter tracks the elapsed time since the beginning of a conversion cycle. Simultaneously, a reference analog signal such as a voltage ramp is generated. When the count provided by the counter reaches a stored digital number value, a sample-and-hold circuit is triggered and acquires the value of the reference analog signal. A multiplicity of stored digital number values can be converted by using a multiplicity of sample-and-hold and trigger circuits. The conversion operations can share the counter and the reference analog signal. The invention can be used to implement massively parallel digital-to-analog conversion. Parallel digital-to-analog conversion is useful in many applications such as digital communications, image display, and shared parallel analog-to-digital conversion where it is desired to convert multiple digital numbers to analog signals.
38 Citations
34 Claims
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1. A machine used for digital-to-analog conversion, comprising:
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a. a first counter which provides a first count b. a first analog reference source which provides a first analog reference signal c. a first digital number value to be converted to a first analog value d. means for causing said first count to change as a function of time e. means for causing said first analog reference signal to change as a function of time f. means for detecting when said first count reaches said first digital number value g. means for recording the value of said first analog reference signal as said first analog value when said first count reaches said first digital number value whereby said first analog value is the converted value of said first digital number value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A machine used for digital-to-analog conversion, comprising:
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a. a first counter which provides a first count b. means for initializing said first count to a first digital number value c. a first analog reference source which provides a first analog reference signal d. means for causing said first count to change as a function of time e. means for causing said first analog reference signal to change as a function of time f. means for detecting when said first count reaches a first digital threshold value g. means for recording the value of said first analog reference signal as said first analog value when said first count reaches said first digital threshold value whereby said first analog value is the converted value of said first digital number value. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. A digital-to-analog converter comprising a first circuit element, wherein:
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a. said first circuit element is used in a first instance for a first conversion of a first digital number to a first analog value b. said first circuit element is also used in said first instance for a second conversion of a second digital number to a second analog value c. said first circuit element comprises a first parameter that varies with time during a conversion operation whereby said first circuit element is effectively shared in said first conversion and in said second conversion, rather than used in said first instance for said first conversion and separately in a second instance for said second conversion, and whereby said first circuit element is not simply a constant reference signal. - View Dependent Claims (28, 29, 30, 31)
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32. A machine used for digital-to-analog conversion, comprising:
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a. a first counter which provides a first count b. means for initializing said first count to a first digital number value c. means for causing said first count to change as a function of time d. means for detecting when said first count reaches a first digital threshold value e. means for averaging the output of said means for detecting when said first count reaches a first digital threshold whereby the output of said means for averaging is the converted value of said first digital number value. - View Dependent Claims (33, 34)
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Specification