Distortion characterization system
View Patent ↗This invention provides a system for evaluating the performance of electronic components and systems by minimizing or eliminating intersymbol interference (ISI). The apparatus includes a transmitter, a device under test, a receiver, and at least one electrical connection between the transmitter and receiver that bypasses the device under test. The electrical connection between the transmitter and receiver transmits information characterizing the intersymbol interference of the transmitted signal to the receiver. The receiver includes an equalizer that uses the information characterizing the intersymbol interference of the transmitted signal to minimize or eliminate intersymbol interference in the received signal where the distortion introduced by the device under test can be isolated and characterized. The methods and devices can be used to evaluate the performance of data transmission systems and components, for example, software models of high-speed data transmission systems, and, among other things, reduces the need for fabricating prototype hardware for testing.
1. A device for characterizing the distortion produced by an electronic component, comprising:
generating a first electrical signal having intersymbol interference; a first channel for transmitting the first electrical signal, the first channel containing the electronic component having a source of signal distortion where a second electrical signal has at least some distortion present;
a second channel for transmitting a third electrical signal containing at least some information characterizing the first electrical signal; and
processing the third electrical signal and the second electrical signal to provide at least some information concerning the distortion produced by the electronic component.
2. The device of claim 1 , where the processing the third electrical signal and the second electrical signal comprises a fourth electrical signal having less intersymbol interference than the second electrical signal.
3. The device of claim 1 , where the third electrical signal and the second electrical signal comprises an equalizer having at least some information characterizing the intersymbol interference of the first electrical signal.
4. The device of claim 1 , where:
a first input for the second electrical signal;
a second input for the third electrical signal; and
removing at least some intersymbol interference from the second electrical signal by an equalizer connected to the first input and the second input.
5. The device of claim 4 , where removing at least some intersymbol interference is accomplished by sampling the second signal to produce at least one bit sequence.
6. The device of claim 4 , where the at least some information characterizing the intersymbol interference comprises at least one intersymbol interference coefficient.
7. The device of claim 1 , where the electronic component is a high speed data transmission device.
8. An electronic signal equalizer for minimizing the content of intersymbol interference in an electrical signal, comprising:
a first input for receiving a first electrical signal having at least some intersymbol interference and at least some distortion other than intersymbol interference;
a second input for receiving a second electrical signal containing at least some information characterizing the first electrical signal;
the second electrical signal further comprises a second series of bit sequences and the means for producing the third electrical signal that comprises subtracting at least one bit sequence from the second series of bit sequences from the first series of bit sequences; and
the equalizer connected to the first input and the second input for producing a third electrical signal having less intersymbol interference than the first signal.
9. The equalizer of claim 8 , further comprising multiplying the at least one bit sequence from the second series of bit sequences by a constant prior to subtracting the at least one bit sequence from the second series of bit sequences.
10. The equalizer of claim 9 , where the constant comprises at least one intersymbol interference coefficient.
11. A signal processing system for producing electrical signals having reduced intersymbol interference, comprising:
a first electrical signal having intersymbol interference;
a first channel for transmitting the first electrical signal, the first channel having a source of signal distortion where a second electrical signal has at least some distortion produced;
a second channel for transmitting a third electrical signal containing at least some information characterizing the first electrical signal; and
an equalizer capable of processing the third electrical and the second electrical signal to produce a fourth electrical signal having less intersymbol interference than the second electrical signal.
12. The signal processing system of claim 11 , where the equalizer comprises:
a first input for the second electrical signal;
a second input for the third electrical signal; and
means connected to the first input and the second input for removing at least some intersymbol interference from the second electrical signal.
13. The signal processing system of claim 12 , where the at least some information characterizing the intersymbol interference comprises at least one intersymbol interference coefficient.
14. The signal processing system of claim 11 , where the source of distortion in the first channel is an electronic device.
15. The signal processing system of claim 14 , where the electronic device is a high speed data transmission device.