Enhanced data converters using compression and decompression
View Patent ↗An enhancement that reduces the digital interface rate of analog-to-digital (A/D) and digital-to-analog (D/A) converters through the use of compression and decompression is described. Improved A/D converters compressing a sampled version of an A/D converter's analog input signal in real time, thereby significantly decreasing the required bit rate of the A/D converter's digital interface. Similarly, improved D/A converters decrease the required bit rate of the D/A converter's digital interface. D/A converters include a decompressor that decompresses the D/A converter's compressed digital input in real time, prior to conversion to an analog output signal.
1. A method of transferring a sampled signal having been sampled at a sample rate between two devices using a data transfer interface, comprising:
in a first device, compressing the sampled signal to form a compressed signal;
transmitting the compressed signal from the first device to a second device using the data transfer interface;
in the second device, receiving the compressed signal from the data transfer interface; and
decompressing the compressed signal to form a decompressed signal, wherein at least one of the compressed signal and the decompressed signal are formed at a rate at least as fast as the sample rate.
2. The method of claim 1 , wherein the data transfer interface used in the step of transmitting comprises a wire or fiber optic cable.
3. The method of claim 1 , wherein the data transfer interface used in the step of transmitting comprises a bus compatible with an industry standard.
4. The method of claim 1 , wherein the data transfer interface used in the step of transmitting comprises a wireless network.
5. The method of claim 1 , further comprising:
producing the sampled signal by converting an analog signal into the sampled signal at the sample rate.
6. The method of claim 1 , further comprising:
converting the decompressed signal into an analog signal at the sample rate.
7. The method of claim 1 , wherein the compressing step operates in one or more compression modes, including at least one of a lossless compression mode and a lossy compression mode.
8. The method of claim 7 , further comprising:
selecting the compression mode for the compressing step in accordance with a compression mode parameter.
9. The method of claim 7 , wherein the lossy compression mode includes at least one of a fixed rate compression mode and a fixed quality compression mode.
10. The method of claim 9 , wherein the compressing step includes one or more of the following:
for the fixed rate compression mode, compressing in accordance with a compression ratio parameter or a bit rate parameter; and
for the fixed quality mode, compressing in accordance with a signal-to-noise ratio parameter or a distortion level parameter.
11. The method of claim 1 , further comprising:
in the first device, storing the sampled signal in a data storage device; and
retrieving the sampled signal from the data storage device for the compressing step.
12. The method of claim 11 , further comprising:
converting an analog signal into the sampled signal at the sample rate.
13. The method of claim 1 , further comprising:
in the second device, storing the compressed signal in a data storage device; and
retrieving the compressed signal from the data storage device for the decompressing step.
14. The method of claim 13 , further comprising:
converting the decompressed signal into an analog signal at the sample rate.
15. The method of claim 1 , further comprising:
in the second device, measuring one or more parameters of the decompressed signal.
16. The method of claim 15 , wherein the parameter is at least one of a time domain signal parameter and a frequency domain signal parameter.
17. A system for transferring a sampled signal having a sample rate from a first device to a second device using a data transfer interface, comprising:
a compressor in the first device coupled to receive the sampled signal and coupled to the data transfer interface, said compressor compressing the sampled signal to form a compressed signal for transmission via the data transfer interface; and
a decompressor in the second device coupled to receive the compressed signal from the data transfer interface and decompressing the compressed signal to form a decompressed signal,
wherein at least one of the compressed signal and the decompressed signal are formed at a rate at least as fast as the sample rate.
18. The system of claim 17 , wherein the data transfer interface comprises a wire or fiber optic cable.
19. The system of claim 17 , wherein the data transfer interface comprises a bus compatible with an industry standard.
20. The system of claim 17 , wherein the data transfer interface comprises a wireless network.
21. The system of claim 17 , further comprising:
an analog-to-digital converter for converting, at the sample rate, an analog signal into the sampled signal and coupled to provide the sampled signal to the compressor.
22. The system of claim 17 , further comprising:
a digital-to-analog converter coupled to receive the decompressed signal and converting, at the sample rate, the decompressed signal into an analog signal.
23. The system of claim 17 , wherein the compressor operates in one or more compression modes, including at least one of a lossless compression mode and a lossy compression mode.
24. The system of claim 23 , further comprising:
a compression mode selector coupled to the compressor for selecting the compression mode in accordance with a compression mode parameter.
25. The system of claim 23 , wherein the lossy compression mode includes at least one of a fixed rate compression mode and a fixed quality compression mode.
26. The system of claim 25 , wherein for the fixed rate compression mode, the compressor operates in accordance with a compression ratio parameter or a bit rate parameter and for the fixed quality mode, the compressor operates in accordance with a signal-to-noise ratio parameter or a distortion level parameter.
27. The system of claim 17 , further comprising:
a data storage device in the first device coupled to receive and store the sampled signal and coupled to the compressor, wherein the compressor retrieves the sampled signal for compression.
28. The system of claim 27 , further comprising:
an analog-to-digital converter for converting an analog signal into the sampled signal at the sample rate and is coupled to provide the sampled signal to the data storage device.
29. The system of claim 17 , further comprising:
a data storage device in the second device coupled to receive and store the compressed signal and coupled to provide the compressed signal to the decompressor.
30. The system of claim 29 , further comprising:
a digital-to-analog converter coupled to receive the decompressed signal and converting, at the sample rate, the decompressed signal into an analog signal.
31. The system of claim 17 , further comprising:
a parameter calculator coupled to receive the decompressed signal and measuring one or more parameters of the decompressed signal.
32. The system of claim 31 , wherein the parameter is at least one of a time domain signal parameter and a frequency domain signal parameter.