Feedback impedance control for driving a signal
A system for driving a first signal onto a wireline includes a driver and feedback circuitry. The driver drives a deterministic signal onto the wireline with an unknown impedance load. The feedback circuitry measures a quality of the output signal from the wireline and modifies a signal strength of the first signal based on the quality of the output signal. The driver then drives the first signal onto the wireline with the modified signal strength.
1. A system for driving a first signal onto a wireline, the system comprising:
a driver configured to drive a deterministic signal onto the wireline with an unknown impedance load and driving the first signal with a modified signal strength onto the wireline;
a digital system coupled to an input of the driver and configured to produce the deterministic signal and the first signal; and
feedback circuitry configured to measure a quality of an output signal from the wireline and modify the signal strength of the first signal based on the quality of the output signal by changing a gain of the first signal in the digital system;
wherein the wireline comprises a residential powerline used for communications.
2. The system of claim 1 wherein the feedback circuitry is configured to modify the signal strength of the first signal by changing a gain of the first signal in an analog system disposed between the digital system and the input of the driver.
3. The system of claim 1 wherein the feedback circuitry is configured to modify the signal strength of the first signal by changing a gain of the first signal in a converter that converts between analog and digital.
4. The system of claim 1 wherein the feedback circuitry is configured to measure the quality of the output signal from the wireline and modify the signal strength of the first signal based on the quality of the output signal until a desired performance of the first signal is achieved.
5. The system of claim 1 wherein the feedback circuitry is configured to measure the quality of the output signal by measuring a distortion of the output signal.
6. The system of claim 1 wherein the feedback circuitry is configured to measure the quality of the output signal by measuring a voltage of the output signal.
7. The system of claim 1 wherein the feedback circuitry is configured to measure the quality of the output signal by measuring a current of the output signal.
8. The system of claim 1 wherein the deterministic signal comprises a test waveform.
9. The system of claim 1 wherein the driver includes an input and an output and the system further comprises a feedback gain circuitry coupled between the output and the input.
10. The system of claim 1 wherein the driver includes an input and an output and wherein the feedback circuitry comprises a measurement system and load limiting logic, the measurement system being coupled between the output of the driver and the load limiting logic and wherein the measurement system is configured to measure the quality of the output signal.
11. The system of claim 1 further comprising an analog system including a digital to analog converter disposed between the digital system and the input of the driver.
12. The system of claim 11 wherein the analog system further includes a digital modulator disposed between the digital system and the digital to analog converter.
13. The system of claim 11 wherein the analog system further includes a current multiplying impedance adaptive line driver coupled between the digital to analog converter and an output of the driver.
14. The system of claim 13 wherein the analog system further includes an impedance adaptation sensor disposed between the current multiplying impedance adaptive line driver and the output of the driver.
15. The system of claim 13 further comprising a coupling unit configured to couple the current multiplying impedance adaptive line driver to an AC power line.
16. The system of claim 1 wherein the driver comprises current sensing circuitry.
17. A method of driving a first signal onto a wireline, the method comprising:
producing a deterministic signal and the first signal by a digital system;
driving the deterministic signal onto the wireline with an unknown impedance load;
measuring a quality of an output signal from the wireline;
modifying the signal strength of the first signal based on the quality of the output signal by changing a gain of the first signal in the digital system; and
driving the first signal onto the wireline with the modified signal strength;
wherein the wireline comprises a residential powerline used for communications.
18. The method of claim 17 wherein modifying the signal strength of the first signal further comprises changing a gain of the first signal in an analog system disposed between the digital system and an input of a driver that drives the deterministic signal and the first signal onto the wireline.
19. The method of claim 17 wherein modifying the signal strength of the first signal further comprises changing a gain of the first signal in a converter that converts between analog and digital.
20. The method of claim 17 wherein measuring the quality of the output signal from the wireline and modifying the signal strength of the first signal based on the quality of the output signal occurs until a desired performance of the first signal is achieved.
21. The method of claim 17 wherein measuring the quality of the output signal comprises measuring a distortion of the output signal.
22. The method of claim 21 wherein measuring the distortion of the output signal includes measuring a signal-to-noise ratio by using a Fast Fourier Transform.
23. The method of claim 17 wherein measuring the quality of the output signal comprises measuring a voltage of the output signal.
24. The method of claim 17 wherein measuring the quality of the output signal comprises measuring a current of the output signal.
25. The method of claim 17 wherein the deterministic signal comprises a test waveform.