US4583188A
Expired / Lapsed
US
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Digitally controlled electronic function generator
Assignee: Lockheed Martin Corp
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Filing: 1983-03-11
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Granted: 1986-04-15
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Expires: 2003-03-11
Abstract
Abstract A new method and apparatus for generating an analog output signal as a function of a digital input in the form of digital words over a specified range. The range is divided into a plurality of intervals, and the function is approximated by a linear segment in each interval. Each linear segment is defined by a step value, which is the value of the linear segment at the beginning the interval, and a slope value, which is the slope of the linear segment in the interval. The function is then approximated for any desired digital word in the range by determining the step and slope values for the interval into which the digital input signal falls, determining an incremental value by multiplying the slope value by the difference between the digital input signal and the value of the digital input signal at the beginning of the interval, and adding the incremental value to the step value.
Inventors
- 👤 Alfred J. Cann
- 👤 Bruce A. Ricker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:46
CPC Classifications
G; G06; G06J; G06J1/00; G06F; G06F1/00; G06F1/02; G06F1/03; G06F1/035; G06F1/0356
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
204 words
A method for generating an analog output signal in response to a digital input signal in the form of input digital words having values in a specified range, the analog output signal being a non-linear function of the digital input, comprising the steps of: (a) approximating the non-linear function by dividing the range into a plurality of intervals, and approximating the function in each interval by a linear segment having an analog step value comprising the value of the linear segment at the beginning of each interval and an analog slope value comprising the rate of change of the linear segment over the interval; (b) determining the interval for the digital input signal; (c) generating the analog step value for the interval from the digital input signal; (d) determining the analog slope value for the interval from the digital input signal; (e) converting the slope value to an analog form slope signal; (f) operating a multiplying digital to analog converter connected to receive as inputs the digital input signal, and the analog form slope signal thereby generating an incremental value in the form of an analog signal; and (g) adding the step value and the analog incremental value to form the analog output signal.
Claim 2
Independent Claim
204 words
A method for generating an analog output signal in response to a digital input signal in the form of input digital words having values in a specified range, the analog output signal being a non-linear function of the digital input, comprising the steps of: (a) approximating the non-linear function by dividing the range into a plurality of intervals, and approximating the function in each interval by a linear segment having an analog step value comprising the value of the linear segment at the beginning of each interval and an analog slope value comprising the rate of change of the linear segment over the interval; (b) determining the interval for the digital input signal; (c) generating the analog step value for the interval from the digital input signal; (d) determining the analog slope value for the interval from the digital input signal; (e) converting the slope value to an analog form slope signal; (f) operating a multiplying digital to analog converter connected to receive as inputs the digital input signal, and the analog form slope signal thereby generating an incremental value in the form of an analog signal; and (g) adding the step value and the analog incremental value to form the analog output signal.
Claim 3
Dependent Claim
73 words
A method as defined in claim 1 in which the step values are a non-linear function of the intervals, and the step (c) of generating the analog step value for the interval further comprises the steps of: (i) using the most significant portion of the input digital word to address a digital step memory to retrieve a digital step word; and (ii) converting the retrieved digital step word to the analog step signal.
Claim 4
Dependent Claim
77 words
A method as defined in claim 2 in which the slope values are a non-linear function of the intervals, the step (d) of determining the slope value for the interval further comprises the steps of: (i) using the most significant portion of the input digital word to address a digital slope memory to retrieve a digital slope word; and (ii) converting the retrieved digital slope word to an analog signal comprising the slope value for the interval.
Claim 5
Dependent Claim
207 words
Apparatus for generating an analog output signal in response to a digital input in the form of an input digital word having a least significant portion and a most significant portion, the apparatus comprising: (a) step digital to analog generating means adapted to receive the most significant portion of the input digital word for generating a step analog output signal in response thereto; (b) slope generating means adapted to receive the most significant portion of the input digital word for generating an output slope signal representative of the rate of change of the analog output signal as a function of the change in digital input over a selected interval of the range of digital input including the input digital word, and (c) increment generating means adapted to receive the least significant portion of the input digital word and the output slope signai, for generating an incremental analog output signal proportional to the least significant portion of the input digital word multiplied by the output slope signal; and (d) analog summing means connected to the step digital to analog generating means and the increment digital to analog generating means, for summing the step anaog output signal and the incremental analog output signal to form the analog output signal.
Claim 6
Dependent Claim
207 words
Apparatus for generating an analog output signal in response to a digital input in the form of an input digital word having a least significant portion and a most significant portion, the apparatus comprising: (a) step digital to analog generating means adapted to receive the most significant portion of the input digital word for generating a step analog output signal in response thereto; (b) slope generating means adapted to receive the most significant portion of the input digital word for generating an output slope signal representative of the rate of change of the analog output signal as a function of the change in digital input over a selected interval of the range of digital input including the input digital word, and (c) increment generating means adapted to receive the least significant portion of the input digital word and the output slope signai, for generating an incremental analog output signal proportional to the least significant portion of the input digital word multiplied by the output slope signal; and (d) analog summing means connected to the step digital to analog generating means and the increment digital to analog generating means, for summing the step anaog output signal and the incremental analog output signal to form the analog output signal.
Claim 7
Dependent Claim
75 words
Apparatus as defined in claim 3 in which the slope generating means comprises: (i) digital slope memory means, having an address input and data output, adapted to receive the most significant portion of the input digital word at the address input, thereby generating a slope digital word at the data output; and (ii) slope digital to analog conversion means connected to receive the slope digital word, thereby generating the output slope signal in analog form.
Claim 8
Dependent Claim
209 words
Apparatus for generating an analog output signal in response to a digital input in the form of an input digital word having a least significant portion and a most significant portion, the apparatus comprising: (a) step digital to analog generating means adapted to receive the most significant portion of the input digital word, for generating a step analog output signal in response thereto; (b) slope generating means adapted to receive the most significant portion of the input digital word for generating a slope analog output signal representative of the rate of change of the analog output signal as a function of the change in digital input over a selected interval of the range of digital input including the input digital word, and (c) a multiplying digital to analog converter having a digital input adapted to receive the least significant portion of the input digital word and a reference input connected to receive the slope analog output signal from said slope generating means; for generating an incremental analog output signal, and; (d) analog summing means connected to the step digital to analog generating means and the multiplying digital to analog converter, for summing the step analog output signal and the incremental analog output signal to form the analog output signal.
Claim 9
Dependent Claim
209 words
Apparatus for generating an analog output signal in response to a digital input in the form of an input digital word having a least significant portion and a most significant portion, the apparatus comprising: (a) step digital to analog generating means adapted to receive the most significant portion of the input digital word, for generating a step analog output signal in response thereto; (b) slope generating means adapted to receive the most significant portion of the input digital word for generating a slope analog output signal representative of the rate of change of the analog output signal as a function of the change in digital input over a selected interval of the range of digital input including the input digital word, and (c) a multiplying digital to analog converter having a digital input adapted to receive the least significant portion of the input digital word and a reference input connected to receive the slope analog output signal from said slope generating means; for generating an incremental analog output signal, and; (d) analog summing means connected to the step digital to analog generating means and the multiplying digital to analog converter, for summing the step analog output signal and the incremental analog output signal to form the analog output signal.
Claim 10
Dependent Claim
88 words
Apparatus as defined in claim 4 in which the step values are a non-linear function of the selected interval, and the step digitial to analog generating means comprises: (i) digital step memory means, having an address input and data output, adapted to receive the most significant portion of the input digital word at the address input, thereby generating a step digital word at the data output; and (ii) step digital to analog conversion means connected to receive the step digital word, thereby generating the step analog output signal.
Claim 11
Dependent Claim
83 words
Apparatus as defined in claim 6 in which the slope values are a non-linear function of the selected interval, and the slope generating means comprises: (i) a digital slope memory, having an address input and data output, adapted to receive the most significant portion of the input digital word at the address input, thereby generating a slope digital word at the data output; and (ii) a slope digital-to-analog converter connected to receive the slope digital word, thereby generating the slope analog output signal.
Claim 12
Dependent Claim
85 words
Apparatus as defined in claim 6 in which the step values are a non-linear function of the selected interval, and the step digital to analog generating means comprises: (i) a digital step memory, having an address input and data output, adapted to receive the most significant portion of the input digital word at the address input, thereby generating a step digital word at the data output; and (ii) a step digital-to-analog converter connected to receive the step digital word, thereby generating the step output signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |