Apparatus and method for adaptive common mode noise decomposition and tuning
Described is an apparatus which comprises: a pre-driver coupled to a transmitter, the transmitter having a differential output; and a tuning circuit operable to couple to the differential output to tune the pre-driver of the transmitter according to a common mode noise signature of a common mode signal derived from the differential output.
1. An apparatus comprising:
a pre-driver to receive input data and to generate one or more outputs;
a transmitter to receive the one or more outputs from the pre-driver, the transmitter having first and second outputs for coupling to a transmission media; and
a tuning circuit coupled to the transmitter, wherein the tuning circuit is operable to:
couple itself to the first and second outputs of the transmitter;
analyze signals on the first and second outputs of the transmitter; and
adjust one or more circuits in the pre-driver according to the analysis.
2. The apparatus of claim 1 comprises:
a first switch to couple the first output to the transmission media; and
a second switch to couple the second output to the transmission media.
3. The apparatus of claim 2 , wherein the tuning circuit comprises an amplifier coupled to the first and second outputs, wherein the amplifier is to generate a common mode signal which is a common mode of the signals of the first and second outputs.
4. The apparatus of claim 3 , wherein the tuning circuit comprises logic to analyze the common mode signal to identify source of common mode noise on the common mode signal.
5. The apparatus of claim 4 , wherein the logic is to analyze the common mode signal when the first and second switches are closed and when the first and second switches are opened.
6. The apparatus of claim 4 , wherein the tuning circuit comprises a controller to adjust the one or more circuits of the pre-driver.
7. The apparatus of claim 6 , wherein the controller is operable to adjust impedance of the transmitter according to the output of the logic.
8. The apparatus of claim 6 , wherein the controller is operable to adjust slew-rate of signals generated by the transmitter according to the output of the logic.
9. The apparatus of claim 6 , wherein the controller is operable to adjust propagation delays of signals generated by the transmitter according to the output of the logic.
10. The apparatus of claim 6 , wherein the controller is operable to adjust amplitude of signals generated by the transmitter according to the output of the logic.
11. The apparatus of claim 1 , wherein the pre-driver includes one or more circuits, and wherein the one or more circuits of the pre-driver include at least one of:
an impedance control circuit to adjust impedance of the transmitter;
a slew-rate control circuit to adjust slew rate of signals generated by the transmitter on the first and second outputs;
a timing control circuit to adjust propagation delay of the signals generated by the transmitter on the first and second outputs; or
an amplitude control circuit to adjust amplitude of the signals generated by the transmitter on the first and second outputs.
12. An apparatus comprising:
a pre-driver coupled to a transmitter, wherein the transmitter has a differential output; and
a tuning circuit operable to couple to the differential output to tune the pre-driver by adjusting one or more circuits of the pre-driver according to a common mode noise signature of a common mode signal derived from the differential output.
13. The apparatus of claim 12 , wherein the differential output includes at least two outputs, wherein the apparatus comprises:
a first switch to couple one of the outputs of the differential output to a transmission media; and
a second switch to couple another of the outputs of the differential output to the transmission media.
14. The apparatus of claim 12 , wherein the tuning circuit comprises an amplifier coupled to the differential output to generate the common mode signal having the common mode noise signature.
15. The apparatus of claim 14 , wherein the tuning circuit comprises a controller to adjust the one or more circuits of the pre-driver according to the common mode noise signature.
16. The apparatus of claim 15 , wherein the controller is operable to adjust slew-rate of signals generated by the transmitter.
17. The apparatus of claim 15 , wherein the controller is operable to adjust an impedance of the transmitter.
18. The apparatus of claim 15 , wherein the controller is operable to adjust amplitude of signals generated by the transmitter.
19. A system comprising:
a memory;
a processor coupled to the memory, the processor having an input-output (I/O) transmitter comprising:
a pre-driver coupled to an analog front end (AFE), the AFE having a differential output; and
a tuning circuit operable to couple to the differential output to tune the pre-driver by adjusting one or more circuits of the pre-driver according to a common mode noise signature of a common mode signal derived from the differential output; and
a wireless interface for allowing the processor to communicate with another device.
20. The system of claim 19 further comprises a display interface for allowing a display unit to display content processed by the processor.