Digital waveform generator and associated method
AssigneeEnertec
InventorFerial Beukara
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Abstract
The present invention relates to synthesis of an analog waveform representative of digital input words but subject to band limiting. In a device for performing such a synthesis a plurality of samples, obtained from the input words by accessing them in memory at a sampling frequency are filtered by a programmable digital filter to yield a plurality of output words which may be fed to a digital to analog converter at a conversion frequency, the converter producing an analog output representative of the input words.
Claims14
A method for producing from a given series of digital input words, an output in the form of an analog waveform approximating, in analog amplitude with respect to time, values of a notional digital signal that would be formed by stepping through each of said digital input words at a stepping frequency selectable over a range of frequencies between a lower stepping frequency limit and an upper stepping frequency limit, said analog waveform having frequency components not exceeding a limiting frequency, comprising the steps of:
- deriving a plurality of digital samples from said digital input words, said samples being equivalent to a sampling of said notional digital signal at a sampling frequency which exceeds said stepping frequency;
- applying said samples to a programmable digital filter arranged to filter said samples to produce a sequence of digital output words, at a predetermined conversion frequency, said conversion frequency being at least twice said limiting frequency and independent of said selected stepping frequency;
- and
- converting said output words from digital form to analog form at said conversion frequency to thereby yield said analog waveform as said output.
A device for producing, from a given series of digital input words, an output in the form of an analog waveform approximating, in analog amplitude with respect to time, values of a notional digital signal that would be formed by stepping through each of said digital input words at a stepping frequency selectable over a range of frequencies between a lower stepping frequency limit and an upper stepping frequency limit, said analog waveform having frequency components not exceeding a limiting frequency, said device comprising:
- sampling means for deriving a plurality of digital samples from said digital input words, said samples being equivalent to a sampling of said notional digital signal at a sampling frequency, said sampling frequency exceeding said stepping frequency;
- a programmable digital filter arranged to filter said samples to produce a sequence of digital output words, at a predetermined conversion frequency, said conversion frequency being at least twice said limiting frequency and independent of said selected stepping frequency, and a digital to analog converter for converting said output words from digital form to analog form at a said conversion frequency to thereby yield said analog waveform as said output.
Dependencies are inferred from the claim text.