Enhanced test and measurement instruments using compression and decompression
First Claim
1. A method of acquiring, compressing, and decompressing signals, comprising:
- receiving an analog input signal at a digital storage oscilloscope including an analog to digital converter, data compression resources, data decompression resources, storage and a display device;
converting, using said analog to digital converter, said analog input signal to a sampled input signal at a sample rate,compressing, using said data compression resources, said sampled input signal into a compressed input signal at a compression rate that is at least as fast as said sample rate, and which represents said sampled input signal with fewer bits,storing said compressed input signal in said storage,retrieving said compressed input signal from said storage and decompressing, using said data decompression resources, said compressed input signal into a decompressed signal,displaying, using said display device, an image based on said decompressed signal.
3 Assignments
0 Petitions
Accused Products
Abstract
An enhancement that improves the performance of test and measurement equipment such as digital oscilloscopes and arbitrary waveform generators through the use of compression and decompression is described. The present invention is particularly effective for compressing and decompressing high-speed, bandlimited analog signals that are not appropriately or cannot effectively be compressed by prior art speech, audio, image, and video compression algorithms due to various limitations of such prior art compression solutions. The present invention improves digital oscilloscopes by compressing the sampled version of an analog waveform under observation in real time, allowing a significantly longer duration of the waveform to be stored in the oscilloscope'"'"'s capture memory, when compared with the duration of the same signal'"'"'s uncompressed waveform stored in the same memory. Similarly, the present invention improves arbitrary waveform generators by storing a compressed version of a desired arbitrary waveform, instead of the uncompressed version of the arbitrary waveform, in the signal generator'"'"'s waveform memory. During signal generation, the compressed waveform is decompressed in real time. The uncompressed waveform drives a D/A converter that generates the desired analog waveform. The present invention'"'"'s simplicity, and its ability to be implemented using parallel compression and decompression elements, allows its use at the high sampling rates of test and measurement instruments. Using the present invention, storage elements in test and measurement equipment can hold significantly longer waveforms in a fixed amount of memory. Users of the present invention can also determine the proper balance between the fidelity and the duration of the decompressed waveform by adjusting various compression and decompression control parameters.
-
Citations
42 Claims
-
1. A method of acquiring, compressing, and decompressing signals, comprising:
-
receiving an analog input signal at a digital storage oscilloscope including an analog to digital converter, data compression resources, data decompression resources, storage and a display device; converting, using said analog to digital converter, said analog input signal to a sampled input signal at a sample rate, compressing, using said data compression resources, said sampled input signal into a compressed input signal at a compression rate that is at least as fast as said sample rate, and which represents said sampled input signal with fewer bits, storing said compressed input signal in said storage, retrieving said compressed input signal from said storage and decompressing, using said data decompression resources, said compressed input signal into a decompressed signal, displaying, using said display device, an image based on said decompressed signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 11, 12)
-
-
10. A method of acquiring, compressing, and decompressing signals, comprising:
-
receiving an analog input signal at a digital storage oscilloscope including storage; converting said analog input signal to a sampled input signal at a sample rate, compressing said sampled input signal into a compressed input signal at a compression rate that is at least as fast as said sample rate, and which represents said sampled input signal with fewer bits, storing said compressed input signal in said storage, retrieving said compressed input signal from said storage and decompressing said compressed input signal into a decompressed signal, displaying an image based on said decompressed signal further including, selecting one of lossless and lossy compression modes, and for the lossy compression mode applying at least one of a desired compression ratio, a desired maximum distortion level. - View Dependent Claims (13)
-
-
14. An apparatus, comprising:
-
an oscilloscope having an input and a display; an analog-to-digital conversion system in the oscilloscope, which converts an analog input signal at the input of the oscilloscope to a sampled input signal at a sample rate at its output, data compressor logic in the oscilloscope and coupled to the output of said analog-to-digital conversion system, that compresses said sampled input signal at a compression rate that is at least as fast as said sample rate, to create a compressed signal, storage, in the oscilloscope and coupled to the output of said data compressor logic, that stores said compressed signal, decompression logic, in the oscilloscope and coupled to the output of said storage, that decompresses said compressed signal into a decompressed signal, a display, in the oscilloscope and coupled to the output of said decompression logic, that displays an image based on said decompressed signal. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
-
-
25. An enhanced digital storage oscilloscope, comprising:
-
an analog-to-digital conversion system, which converts an analog input signal at an input of an oscilloscope to a sampled input signal at a sample rate at its output, data compressor logic, coupled to the output of said analog-to-digital conversion system, that compresses said sampled input signal at a compression rate that is at least as fast as said sample rate, to create a compressed signal, storage, coupled to the output of said data compressor logic, that stores said compressed signal, decompression logic, coupled to the output of said storage, that decompresses said compressed signal into a decompressed signal, a display, coupled to the output of said decompression logic, that displays an image based on said decompressed signal, further including compression control logic for selecting one of a lossless and a lossy compression modes, for the lossy compression mode, applying at least one of a desired compression ratio, a desired maximum distortion level. - View Dependent Claims (26)
-
-
27. In an enhanced arbitrary waveform signal generator including storage, decompression resources and a digital to analog converter operating at a sample rate, a method for generating an analog output signal from a compressed signal, comprising:
-
storing a compressed signal representing a digitized arbitrary waveform signal in the storage, retrieving said compressed signal from said signal generator storage and decompressing, using the decompression resources, said compressed signal at a decompression rate that is at least as fast as the sample rate to generate an uncompressed sampled signal, converting, using the digital to analog converter, said uncompressed sampled signal into an analog output signal at a said sample rate, the analog output signal representing said arbitrary waveform signal. - View Dependent Claims (28, 29, 30, 31, 32, 33)
-
-
34. In an enhanced arbitrary waveform signal generator including storage, decompression resources and a digital to analog converter, a method for generating an analog output signal from a compressed signal, comprising:
-
storing a compressed signal representing a digitized arbitrary waveform signal in the storage, the digitized arbitrary waveform being digitized at a sample rate, retrieving said compressed signal from said signal generator storage and decompressing, using the decompression resources, said compressed signal at a decompression rate that is at least as fast as the sample rate to generate an uncompressed sampled signal, converting, using the digital to analog converter an said uncompressed sampled signal into an analog output signal at a said sample rate, the analog output signal representing said arbitrary waveform signal in which said decompressing step includes lossless decoding that converts said compressed signal into said uncompressed sampled signal.
-
-
35. An apparatus, comprising:
-
a waveform generator including a digital-to-analog converter operating at a sample rate; a signal generator interface on the waveform generator that receives a compressed signal representing a digitized arbitrary waveform, signal generator storage in the waveform generator that receives and stores said compressed signal, decompression logic in the waveform generator, coupled to the output of said signal generator storage, which decompresses said compressed signal at a decompression rate that is at least as fast as the sample rate to create an uncompressed sampled signal, the digital-to-analog converter, in the waveform generator and coupled to the output of said decompression logic and operating at the sample rate that converts said uncompressed sampled signal to an analog output signal representing the arbitrary waveform signal. - View Dependent Claims (36, 37, 38, 39, 40, 41)
-
-
42. An enhanced arbitrary waveform signal generator, comprising:
-
a signal generator interface that receives a compressed signal representing a digitized arbitrary waveform, the digitized arbitrary waveform being digitized at a sample rate, signal generator storage that receives and stores said compressed signal, decompression logic, coupled to the output of said signal generator storage, which decompresses said compressed signal at a decompression rate that is at least as fast as the sample rate to create an uncompressed sampled signal, a digital-to-analog converter, coupled to the output of said decompression logic and operating at said sample rate that converts said uncompressed sampled signal to an analog output signal representing the arbitrary waveform signal in which said decompression logic includes a lossless decoder that converts said compressed signal into said uncompressed sampled signal.
-
Specification