Electromagnetic power measurement and reporting
View Patent ↗A method to measure and report electromagnetic radiation power includes receiving electromagnetic radiation and generating an electrical signal in response to the received electromagnetic radiation. The electrical signal may have a magnitude based on the power of the electromagnetic radiation. The method also includes applying a logarithmic gain to the electrical signal to generate a logarithmically amplified electrical signal. The method also includes sampling the logarithmically amplified electrical signal to generate a digital sample of the logarithmically amplified electrical signal.
1. A method, comprising:
receiving electromagnetic radiation;
generating a first electrical signal in response to the received electromagnetic radiation, a magnitude of the first electrical signal based on a power of the electromagnetic radiation;
generating a second electrical signal based on the magnitude of the first electrical signal;
applying a logarithmic gain to the second electrical signal to generate a logarithmically amplified electrical signal; and
sampling the logarithmically amplified electrical signal to generate a digital sample of the logarithmically amplified electrical signal.
2. The method of claim 1 , wherein the generating the second electrical signal comprises generating the second electrical signal at a precision current mirror circuit.
3. The method of claim 2 , wherein the first second electrical signal comprises a mirrored current of the first electrical signal.
4. The method of claim 3 , wherein the generating the first electrical signal in response to the received electromagnetic radiation comprises generating the first electrical signal at a photodiode.
5. The method of claim 1 , further comprising compressing the logarithmically amplified electrical signal such that a dynamic range of the compressed logarithmically amplified electrical signal fits within a particular resolution zone of an analog to digital converter configured to sample the logarithmically amplified electrical signal to generate the digital sample.
6. The method of claim 5 , further comprising applying temperature compensation to the compressed logarithmically amplified electrical signal to generate a temperature compensated logarithmically amplified electrical signal.
7. The method of claim 1 , further comprising:
receiving the digital sample; and
calculating the power of the electromagnetic radiation by applying one or more calibration factors to the digital sample.
8. The method of claim 7 , wherein the one or more calibration factors comprises a slope term and an offset term.
9. The method of claim 7 , wherein the one or more calibration factors comprise at least one of an exponential function, a polynomial function, or a logarithmic function.
10. The method of claim 7 , wherein the one or more calibration factors are arranged in a look-up table.
11. The method of claim 7 , wherein the power of the electromagnetic radiation is formatted and reported in units of Decibel-milliwatts (dBm) utilizing a scale that ranges from approximately +128.000 dBm to −128.000 dBm.
12. The method of claim 1 , wherein the logarithmic gain has a slope ranging from about twenty four to about twenty seven millivolts per Decibel (dB).
13. A system, comprising:
a photodiode configured to receive electromagnetic radiation and generate a first electrical signal in response to the received electromagnetic radiation, a magnitude of the first electrical signal based on a power of the electromagnetic radiation;
a circuit electrically coupled to the photodiode and configured to generate a second electrical signal based on the magnitude of the first electrical signal;
a logarithmic amplifier electrically coupled to the circuit and configured to apply a logarithmic gain to the second electrical signal to generate a logarithmically amplified electrical signal; and
an analog-to-digital converter electrically coupled to the logarithmic amplifier and configured to sample the logarithmically amplified signal and generate a digital sample.
14. The system of claim 13 , wherein the circuit comprises a precision current mirror circuit.
15. The system of claim 13 , wherein the photodiode comprises an avalanche photodiode.
16. The system of claim 13 , further comprising a buffer amplifier circuit electrically coupled between the logarithmic amplifier and the analog-to-digital converter and configured to compress the logarithmically amplified electrical signal such that a dynamic range of the compressed logarithmically amplified electrical signal fits within a particular resolution zone of the analog to digital converter.
17. The system of claim 16 , further comprising a temperature compensation circuit electrically coupled between the buffer amplifier circuit and the analog-to-digital converter and configured to apply temperature compensation to the compressed logarithmically amplified electrical signal to generate a temperature compensated logarithmically amplified electrical signal.
18. The system of claim 13 , further comprising a power calculation module communicatively coupled to the analog-to-digital converter, the power calculation module configured to:
receive the digital sample; and
calculate the power of the electromagnetic radiation by applying one or more calibration factors to the digital sample.
19. The system of claim 18 , wherein the one or more calibration factors comprise a slope term and an offset term.
20. The system of claim 18 , wherein the power of the electromagnetic radiation is formatted and reported in units of Decibel-milliwatts (dBm) utilizing a scale that ranges from approximately +128.000 dBm to −128.000 dBm.