Instrumentation & Measurement Magazine 23-5 - 47
Fig. 7. Magnetic field measurement experiment field. (a) Three-dimensional double layer cube standard magnetic field generation coils; (b) The picture when
comparative experiments were made.
RMSDs mentioned above were calculated by 100 samples in
the experiments.
First Comparative Experiment: The RMSD varies as the length
of the measurement time. A standard sine signal with the amplitude 2 Vpp and the frequency 2000 Hz was generated by
signal generator. A random noise produced by the same generator with the amplitude 0.05 Vpp and the bandwidth 20 MHz
was added to the standard sine signal. Hence, the peak-to-peak
SNR of generated signal is about 32 dB. The measurement time
length of all methods was set from 100 ms to 1000 ms in 50-ms
steps. The results are displayed in Fig. 8. Fig. 8a indicates that
the RMSD of the proposed method is much smaller than the
MPM method mentioned in [16]. Assuming that the required
RMSD of a PM is 0.02 nT (according to (1), the absolute precision of the frequency measurement is 0.001 Hz), the required
measurement time length of the proposed method is about
250 ms. However, 700 ms is the least demand for the MPM
method. Therefore, it is easier to realize fast measurement if
the proposed method is adopted. It is shown in Fig. 8b that the
RMSD of the proposed method is better than that adopting
only rising or falling edge, especially when the measurement
time length is less than 300 ms.
Second Comparative Experiment: The RMSD varies as the
different SNR. The frequency of a tested sine signal was set
to 2000 Hz, the amplitude was varied from 0.4 Vpp to 3 Vpp,
and the step was set to 0.2 Vpp. A random noise, which the
amplitude is 0.05 Vpp, was added to the tested sine signal.
So, the SNR of the tested signal was varied from 18.1 dB to
35.5 dB. In addition, the length of the measurement time was
set to 600 ms for all of the methods. The experimental results are shown in Fig. 9. Fig. 9a indicates that the proposed
method is better than MPM to deal with the noised sine signal. The RMSD of the proposed method is less than 0.0006 Hz
if the SNR of the noised sine signal is larger than 18 dB. However, if the same RMSD are demanded for the MPM method,
the SNR must be larger than 34 dB. Fig. 9b indicates that if the
Fig. 8. The RMSD varies as measurement time comparative experiment. (a) Comparison between the MPM method and the M-MFM method using both edges; (b)
Comparisons between the three cases of the M-MFM method: using both edges, using only the rising edge, and using only the falling edge.
August 2020
IEEE Instrumentation & Measurement Magazine 47
Instrumentation & Measurement Magazine 23-5
Table of Contents for the Digital Edition of Instrumentation & Measurement Magazine 23-5
No label
Instrumentation & Measurement Magazine 23-5 - No label
Instrumentation & Measurement Magazine 23-5 - Cover2
Instrumentation & Measurement Magazine 23-5 - 1
Instrumentation & Measurement Magazine 23-5 - 2
Instrumentation & Measurement Magazine 23-5 - 3
Instrumentation & Measurement Magazine 23-5 - 4
Instrumentation & Measurement Magazine 23-5 - 5
Instrumentation & Measurement Magazine 23-5 - 6
Instrumentation & Measurement Magazine 23-5 - 7
Instrumentation & Measurement Magazine 23-5 - 8
Instrumentation & Measurement Magazine 23-5 - 9
Instrumentation & Measurement Magazine 23-5 - 10
Instrumentation & Measurement Magazine 23-5 - 11
Instrumentation & Measurement Magazine 23-5 - 12
Instrumentation & Measurement Magazine 23-5 - 13
Instrumentation & Measurement Magazine 23-5 - 14
Instrumentation & Measurement Magazine 23-5 - 15
Instrumentation & Measurement Magazine 23-5 - 16
Instrumentation & Measurement Magazine 23-5 - 17
Instrumentation & Measurement Magazine 23-5 - 18
Instrumentation & Measurement Magazine 23-5 - 19
Instrumentation & Measurement Magazine 23-5 - 20
Instrumentation & Measurement Magazine 23-5 - 21
Instrumentation & Measurement Magazine 23-5 - 22
Instrumentation & Measurement Magazine 23-5 - 23
Instrumentation & Measurement Magazine 23-5 - 24
Instrumentation & Measurement Magazine 23-5 - 25
Instrumentation & Measurement Magazine 23-5 - 26
Instrumentation & Measurement Magazine 23-5 - 27
Instrumentation & Measurement Magazine 23-5 - 28
Instrumentation & Measurement Magazine 23-5 - 29
Instrumentation & Measurement Magazine 23-5 - 30
Instrumentation & Measurement Magazine 23-5 - 31
Instrumentation & Measurement Magazine 23-5 - 32
Instrumentation & Measurement Magazine 23-5 - 33
Instrumentation & Measurement Magazine 23-5 - 34
Instrumentation & Measurement Magazine 23-5 - 35
Instrumentation & Measurement Magazine 23-5 - 36
Instrumentation & Measurement Magazine 23-5 - 37
Instrumentation & Measurement Magazine 23-5 - 38
Instrumentation & Measurement Magazine 23-5 - 39
Instrumentation & Measurement Magazine 23-5 - 40
Instrumentation & Measurement Magazine 23-5 - 41
Instrumentation & Measurement Magazine 23-5 - 42
Instrumentation & Measurement Magazine 23-5 - 43
Instrumentation & Measurement Magazine 23-5 - 44
Instrumentation & Measurement Magazine 23-5 - 45
Instrumentation & Measurement Magazine 23-5 - 46
Instrumentation & Measurement Magazine 23-5 - 47
Instrumentation & Measurement Magazine 23-5 - 48
Instrumentation & Measurement Magazine 23-5 - 49
Instrumentation & Measurement Magazine 23-5 - 50
Instrumentation & Measurement Magazine 23-5 - 51
Instrumentation & Measurement Magazine 23-5 - 52
Instrumentation & Measurement Magazine 23-5 - 53
Instrumentation & Measurement Magazine 23-5 - 54
Instrumentation & Measurement Magazine 23-5 - 55
Instrumentation & Measurement Magazine 23-5 - 56
Instrumentation & Measurement Magazine 23-5 - 57
Instrumentation & Measurement Magazine 23-5 - 58
Instrumentation & Measurement Magazine 23-5 - 59
Instrumentation & Measurement Magazine 23-5 - 60
Instrumentation & Measurement Magazine 23-5 - 61
Instrumentation & Measurement Magazine 23-5 - 62
Instrumentation & Measurement Magazine 23-5 - 63
Instrumentation & Measurement Magazine 23-5 - 64
Instrumentation & Measurement Magazine 23-5 - 65
Instrumentation & Measurement Magazine 23-5 - 66
Instrumentation & Measurement Magazine 23-5 - 67
Instrumentation & Measurement Magazine 23-5 - 68
Instrumentation & Measurement Magazine 23-5 - Cover3
Instrumentation & Measurement Magazine 23-5 - Cover4
https://www.nxtbook.com/allen/iamm/26-6
https://www.nxtbook.com/allen/iamm/26-5
https://www.nxtbook.com/allen/iamm/26-4
https://www.nxtbook.com/allen/iamm/26-3
https://www.nxtbook.com/allen/iamm/26-2
https://www.nxtbook.com/allen/iamm/26-1
https://www.nxtbook.com/allen/iamm/25-9
https://www.nxtbook.com/allen/iamm/25-8
https://www.nxtbook.com/allen/iamm/25-7
https://www.nxtbook.com/allen/iamm/25-6
https://www.nxtbook.com/allen/iamm/25-5
https://www.nxtbook.com/allen/iamm/25-4
https://www.nxtbook.com/allen/iamm/25-3
https://www.nxtbook.com/allen/iamm/instrumentation-measurement-magazine-25-2
https://www.nxtbook.com/allen/iamm/25-1
https://www.nxtbook.com/allen/iamm/24-9
https://www.nxtbook.com/allen/iamm/24-7
https://www.nxtbook.com/allen/iamm/24-8
https://www.nxtbook.com/allen/iamm/24-6
https://www.nxtbook.com/allen/iamm/24-5
https://www.nxtbook.com/allen/iamm/24-4
https://www.nxtbook.com/allen/iamm/24-3
https://www.nxtbook.com/allen/iamm/24-2
https://www.nxtbook.com/allen/iamm/24-1
https://www.nxtbook.com/allen/iamm/23-9
https://www.nxtbook.com/allen/iamm/23-8
https://www.nxtbook.com/allen/iamm/23-6
https://www.nxtbook.com/allen/iamm/23-5
https://www.nxtbook.com/allen/iamm/23-2
https://www.nxtbook.com/allen/iamm/23-3
https://www.nxtbook.com/allen/iamm/23-4
https://www.nxtbookmedia.com