Noise modulation for on-chip noise measurement
Functionality for estimating characteristics of an on-chip noise signal can be implemented on a processing module. An on-chip noise signal is determined at an on-chip determination point of a computer chip. The on-chip noise signal is converted to a frequency-varying signal using a voltage-controlled oscillator implemented on the computer chip. The frequency-varying signal is measured at an off-chip measurement point and frequency information is extracted from the frequency-varying signal. The frequency information is converted to a voltage level associated with the on-chip noise signal based on the relationship between an input voltage provided to the voltage-controlled oscillator and an output frequency generated by the voltage-controlled oscillator.
1. A device for estimating a voltage level of an on-chip noise signal of a computer chip, the device comprising:
a voltage-to-frequency conversion structure that represents a relationship between an input voltage provided to a voltage-controlled oscillator on the computer chip and an output frequency generated by the voltage-controlled oscillator; and
a noise estimation unit comprising at least one member of the group consisting of an integrated circuit and a processor with associated memory that is external to the computer chip, the noise estimation unit configured to:
receive a frequency-varying signal that is representative of the on-chip noise signal determined at a determination point on the computer chip;
extract frequency information from the frequency-varying signal; and
convert the frequency information to the voltage level associated with the on-chip noise signal based, at least in part, on the voltage-to-frequency conversion structure.
2. The device of claim 1 , wherein the noise estimation unit configured to extract the frequency information from the frequency-varying signal and convert the frequency information to the voltage level associated with the on-chip noise signal comprises the noise estimation unit configured to:
execute windowing operations on the frequency-varying signal to yield a subset of the frequency-varying signal;
execute time-to-frequency domain conversion operations to convert the subset of the frequency-varying signal to a corresponding frequency domain signal; and
determine the voltage level associated with the on-chip noise signal based, at least in part, on the frequency information extracted from the frequency domain signal and the voltage-to-frequency conversion structure.
3. The device of claim 2 , wherein the noise estimation unit configured to determine the voltage level associated with the on-chip noise signal comprises the noise estimation unit configured to:
determine that an amplitude of the frequency domain signal exceeds a predefined threshold at a first frequency of the frequency domain signal;
identify the first frequency as a resonant frequency of the frequency domain signal, wherein the frequency information includes the resonant frequency; and
convert the resonant frequency to the voltage level associated with the on-chip noise signal based, at least in part, on the voltage-to-frequency conversion structure.
4. The device of claim 2 , wherein the noise estimation unit is further configured to:
determine a variation in the voltage level with time based, at least in part, on the frequency information, the voltage-to-frequency conversion structure, and a time interval that corresponds to the subset of the frequency-varying signal.
5. The device of claim 1 , wherein the noise estimation unit is further configured to:
determine a reference output frequency of an output signal generated by the voltage-controlled oscillator for each of a plurality of reference direct current (DC) signals provided to the voltage-controlled oscillator; and
determine the voltage-to-frequency conversion structure based, at least in part, on the plurality of reference DC signals and the corresponding reference output frequency.
6. The device of claim 1 , wherein the integrated circuit comprises a system on a chip.
7. The device of claim 1 , wherein the integrated circuit comprises an application specific integrated circuit.
8. A system comprising:
a computer chip comprising a voltage-controlled oscillator configured to:
convert an on-chip noise signal determined at a determination point on the computer chip to a frequency-varying signal; and
provide the frequency-varying signal to an off-chip noise estimation unit that is external to the computer chip;
the off-chip noise estimation unit coupled with 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 configured to:
extract frequency information from the frequency-varying signal received from the voltage-controlled oscillator; and
convert the frequency information to a voltage level associated with the on-chip noise signal based, at least in part, on a voltage-to-frequency conversion structure.
9. The system of claim 8 , wherein the off-chip noise estimation unit configured to extract the frequency information from the frequency-varying signal and convert the frequency information to the voltage level associated with the on-chip noise signal comprises the off-chip noise estimation unit configured to:
execute windowing operations on the frequency-varying signal to yield a subset of the frequency-varying signal;
execute time-to-frequency domain conversion operations to convert the subset of the frequency-varying signal to a corresponding frequency domain signal;
determine that an amplitude of the frequency domain signal exceeds a predefined threshold at a resonant frequency of the frequency domain signal, wherein the frequency information includes the resonant frequency; and
convert the resonant frequency to the voltage level associated with the on-chip noise signal based, at least in part, on a relationship between an input voltage provided to the voltage-controlled oscillator and an output frequency generated by the voltage-controlled oscillator.
10. The system of claim 9 , wherein the off-chip noise estimation unit is further configured to:
determine 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.
11. The system of claim 8 , wherein the off-chip noise estimation unit is further configured to:
determine an output frequency of an output signal generated by the voltage-controlled oscillator for each of a plurality of reference direct current (DC) signals provided to the voltage-controlled oscillator; and
determine the voltage-to-frequency conversion structure based, at least in part, on the plurality of reference DC signals and the corresponding output frequency, wherein the off-chip noise estimation unit is configured to convert the frequency information to the voltage level associated with the on-chip noise signal using the voltage-to-frequency conversion structure.
12. The system of claim 8 , wherein the computer chip further comprises a noise determination unit configured to:
determine the on-chip noise signal at the determination point on the computer chip; and
provide the on-chip noise signal as an input to the voltage-controlled oscillator.
13. The system of claim 8 , wherein the integrated circuit comprises a system on a chip.
14. The system of claim 8 , wherein the integrated circuit comprises an application specific integrated circuit.