Published October 1, 2015 | Version accepted
Journal article Open

Techniques for Schumann Resonance Measurements: A Comparison of Four Amplifiers With a Noise Floor Estimate

Authors/Creators

  • 1. Universidad de Almería, Almería, Spain

Description

Schumann resonances are very weak natural electromagnetic signals produced in the earth–ionosphere cavity located in the extremely low frequency (ELF) band (7–60 Hz), and the sensors that measure them produce amplitudes of few microvolts. Strong signals from power lines (50–60 Hz) occur in the same frequency range. Amplification techniques play a key role in acquiring resonance modes with the best signal-to-noise (S/N) ratio. This paper presents a study of the various structures of amplification systems that optimize the S/N ratio for the signal of interest. The aim of this paper is to measure all possible resonance modes with low time acquisition. To this end, we compare four instrumentation amplifiers and design a new indirect method for obtaining the noise floor of the system with sensors manufactured on magnetic cores that are several meters long. We present the measurements of the Schumann resonance achieved using these techniques at the ELF electromagnetic wave observatory at Calar Alto (Spain). The solutions adopted allow measurement of seven resonance modes with an acquisition time of 30 min, where the S/N ratio in the fundamental mode was 39 dB.

Abstract (English)

Schumann resonances are very weak natural electromagnetic signals produced in the earth–ionosphere cavity located in the extremely low frequency (ELF) band (7–60 Hz), and the sensors that measure them produce amplitudes of few microvolts. Strong signals from power lines (50–60 Hz) occur in the same frequency range. Amplification techniques play a key role in acquiring resonance modes with the best signal-to-noise (S/N) ratio. This paper presents a study of the various structures of amplification systems that optimize the S/N ratio for the signal of interest. The aim of this paper is to measure all possible resonance modes with low time acquisition. To this end, we compare four instrumentation amplifiers and design a new indirect method for obtaining the noise floor of the system with sensors manufactured on magnetic cores that are several meters long. We present the measurements of the Schumann resonance achieved using these techniques at the ELF electromagnetic wave observatory at Calar Alto (Spain). The solutions adopted allow measurement of seven resonance modes with an acquisition time of 30 min, where the S/N ratio in the fundamental mode was 39 dB.

Files

2015-accepted_Techniques for Schumann Resonance.pdf

Files (1.4 MB)

Additional details

Identifiers

DOI
10.1109/TIM.2015.2420376

Related works

Is previous version of
Journal article: 10.1109/TIM.2015.2420376 (DOI)

Dates

Available
2015-06-15
Available

References

  • J. A. Gázquez Parra, M. F. Ros, N. N. Castellano and R. M. G. Salvador, "Techniques for Schumann Resonance Measurements: A Comparison of Four Amplifiers With a Noise Floor Estimate," in IEEE Transactions on Instrumentation and Measurement, vol. 64, no. 10, pp. 2759-2768, Oct. 2015, doi: 10.1109/TIM.2015.2420376.