Noise modulation for on-chip noise measurement

1. A method comprising:

determining an on-chip noise signal at an on-chip determination point on a computer chip;

converting, using a voltage-controlled oscillator, the on-chip noise signal to a frequency-varying signal;

providing the frequency-varying signal to an off-chip noise estimation unit that is external to the computer chip, the off-chip noise estimation unit comprising at least one member of the group consisting of an integrated circuit and a processor with associated memory;

executing, by the off-chip noise estimation unit, windowing operations on the frequency-varying signal to yield a subset of the frequency-varying signal;

executing, by the off-chip noise estimation unit, time-to-frequency domain conversion operations to convert the subset of the frequency-varying signal to a corresponding frequency domain signal; and

determining, by the off-chip noise estimation unit, a voltage level associated with the on-chip noise signal based, at least in part, on frequency information extracted from the frequency domain signal and a relationship between an input voltage provided to the voltage-controlled oscillator and an output frequency generated by the voltage-controlled oscillator.

2. The method of claim 1 , wherein the voltage-controlled oscillator is implemented on the computer chip.

3. The method of claim 1 , wherein an instantaneous frequency of the frequency-varying signal varies according to an instantaneous voltage level of the on-chip noise signal.

4. The method of claim 1 , wherein said determining the voltage level associated with the on-chip noise signal comprises:

determining that an amplitude of the frequency domain signal exceeds a predefined threshold at a first frequency of the frequency domain signal;

designating the first frequency as a resonant frequency of the frequency domain signal, wherein the frequency information includes the resonant frequency; and

converting the resonant frequency to the voltage level associated with the on-chip noise signal based, at least in part, on the relationship between the input voltage provided to the voltage-controlled oscillator and the output frequency generated by the voltage-controlled oscillator.

5. The method of claim 1 , further comprising:

determining a variation in the voltage level with time based, at least in part, on the frequency information and a time interval that corresponds to the subset of the frequency-varying signal.

6. The method of claim 1 , further comprising:

calibrating the voltage-controlled oscillator to determine the relationship between the input voltage provided to the voltage-controlled oscillator and the output frequency generated by the voltage-controlled oscillator for said determining the voltage level associated with the on-chip noise signal.

7. The method of claim 1 , further comprising:

for each of a plurality of reference direct current (DC) signals provided to the voltage-controlled oscillator, determining an output frequency of an output signal generated by the voltage-controlled oscillator; and

determining a voltage-to-frequency conversion structure based, at least in part, on the plurality of reference DC signals and the corresponding output frequency; and

using the voltage-to-frequency conversion structure for said determining the voltage level associated with the on-chip noise signal.

8. The method of claim 7 , wherein the output signal generated by the voltage-controlled oscillator for each of the plurality of reference DC signals is measured external to the computer chip.

9. The method of claim 1 , further comprising:

determining whether to execute noise cancellation operations at the computer chip based on at least one of the voltage level associated with the on-chip noise signal and an application executing on the computer chip.

10. The method of claim 1 , wherein the integrated circuit comprises a system on a chip.

11. The method of claim 1 , wherein the integrated circuit comprises an application specific integrated circuit.