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US 11,146,280 B2Granted
Digital signal processing waveform synthesis for fixed sample rate signal sources
AssigneeTektronix, Inc.
InventorsGregory A. Martin, Patrick Satarzadeh, John J. Pickerd, Daniel G. Knierim
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Abstract
A test and measurement instrument including a digital-to-analog converter having an output sample rate configured to receive a digital sample waveform and a reference clock and output an analog waveform at the sample rate, a waveform synthesizer configured to receive an input waveform having a baud rate and output a digital sample waveform having a baud rate less than the sample rate of the digital-to-analog converter, and a port configured to output the analog waveform.
Claims20
A test and measurement instrument, comprising:
- a digital-to-analog converter having an output sample rate configured to receive a digital sample waveform and a reference clock and output an analog waveform at the sample rate;
- a waveform synthesizer configured to receive an input waveform having a baud rate less than the sample rate of the digital-to-analog converter by a non-integer rational ratio and to provide the digital sample waveform;
- and
- a port configured to output the analog waveform,
- wherein the waveform synthesizer operates in real-time,
- wherein the waveform synthesizer includes:
- a waveform replicator configured to up-sample the input waveform by an integer factor N, where N is greater than 1;
- a low-pass filter configured to receive the up-sampled input waveform and remove waveform content above the Nyquist frequency of the digital-to-analog converter;
- and
- a down-sampler configured to down-sample the filtered up-sampled input waveform to match the output sample rate.
7 more elements
A test and measurement instrument, comprising:
- a digital-to-analog converter having an output sample rate configured to receive a digital sample waveform and a reference clock and output an analog waveform at the sample rate;
- a waveform synthesizer configured to receive an input waveform having a baud rate less than the sample rate of the digital-to-analog converter by a non-integer rational ratio and to provide the digital sample waveform;
- and
- a port configured to output the analog waveform,
- wherein the waveform synthesizer operates in real-time,
- wherein the waveform synthesizer includes:
- a waveform symbol clock generator configured to receive the reference clock and output a symbol transition event and a symbol transition sub-sample phase;
- and
- an edge interpolator configured to receive the input waveform, the symbol transition event, and the symbol transition sub-sample phase and output the digital sample waveform having the baud rate less than the sample rate of the digital-to-analog converter by a rational ratio of the baud rate and the digital-to-analog converter sample rate.
6 more elements
A method for synthesizing a waveform, comprising:
- converting a digital sample waveform through a digital-to-analog converter having a fixed output sample rate to an analog waveform at the sample rate;
- receiving an input waveform having a baud rate less than the output sample rate of the digital-to-analog converter by a non-integer rational ratio;
- synthesizing a digital sample waveform from the input waveform through a waveform synthesizer;
- and
- outputting the analog waveform to a device under test,
- wherein synthesizing the digital sample waveform includes synthesizing the digital sample waveform in real-time,
- wherein synthesizing the waveform includes:
- up-sampling the input waveform by an integer factor N, where N is greater than 1;
- filtering the up-sampled waveform to remove waveform content above the Nyquist frequency of the digital-to-analog converter;
- and
- down-sampling the filtered up-sampled input waveform to match the fixed output sample rate.
8 more elements
A method for synthesizing a waveform, comprising:
- converting a digital sample waveform through a digital-to-analog converter having a fixed output sample rate to an analog waveform at the sample rate;
- receiving an input waveform having a baud rate less than the output sample rate of the digital-to-analog converter by a non-integer rational ratio;
- synthesizing a digital sample waveform from the input waveform through a waveform synthesizer;
- and
- outputting the analog waveform to a device under test,
- wherein synthesizing the digital sample waveform includes synthesizing the digital sample waveform in real-time,
- wherein synthesizing the waveform includes:
- generating a symbol transition event and a symbol transition sub-sample phase based on a reference clock used by the digital-to-analog converter;
- and
- generating the digital sample waveform having a baud rate less than the sample rate of the digital-to-analog converter based on the input waveform, the symbol transition event, and the symbol transition sub-sample phase.
7 more elements
One or more non-transitory computer-readable storage media comprising instructions, which, when executed by one or more processors of a test and measurement instrument, cause the test and measurement instrument to:
- convert a digital sample waveform through a digital-to-analog converter having an output sample rate to an analog waveform at the sample rate;
- receive an input waveform having a baud rate less than the output sample rate of the digital-to-analog converter by a non-integer rational ratio;
- synthesize a digital sample waveform from the input waveform in real-time through a waveform synthesizer;
- and
- output the analog waveform to a device under test, further including instructions to synthesize the waveform by:
- up-sampling the input waveform by an integer factor N, where N is greater than 1;
- filtering the up-sampled waveform to remove waveform content above the Nyquist frequency of the digital-to-analog converter;
- and
- down-sampling by an integer factor, the filtered up-sampled input waveform to obtain the desired output sample rate.
6 more elements
Dependencies are inferred from the claim text.