A review of demodulation techniques for multifrequency atomic force microscopy

• David M. Harcombe,
• Michael G. Ruppert and
• Andrew J. Fleming

Beilstein J. Nanotechnol. 2020, 11, 76–91, doi:10.3762/bjnano.11.8

• estimation analysis Amplitude estimation performance of the three-channel multifrequency demodulators was investigated when a three-tone sinewave was applied as an input signal described by Equation 2. Here, A1 = 500 mV, A2 = 100 mV, A3 = 50 mV, f1 = 50 kHz, f2 = 150 kHz, and f3 = 300 kHz. Figure 9 shows the

• amplitude estimation error () in the time-domain and amplitude estimate power spectral density (PSD) for both low (1%fi) and high (50%fi) tracking bandwidth settings. When the three-tone sinewave is applied, the performance of each demodulator at low bandwidths is shown to be similar. Each channel is able

• (blue), f2 = 150 kHz (red) and f3 = 300 kHz (yellow). Experimental amplitude estimation error and power spectral density of amplitude estimation for the (a) lock-in amplifier, (b) coherent demodulator, (c) Kalman filter, (d) Lyapunov filter and (e) direct-design method for low (1%fi) and high (50%fi

A review of demodulation techniques for amplitude-modulation atomic force microscopy

• Michael G. Ruppert,
• David M. Harcombe,
• Michael R. P. Ragazzon,
• S. O. Reza Moheimani and
• Andrew J. Fleming

Beilstein J. Nanotechnol. 2017, 8, 1407–1426, doi:10.3762/bjnano.8.142

• constant-height mode. Keywords: amplitude estimation; atomic force microscopy; amplitude modulation; digital signal processing; field-programmable gate array; Introduction Amplitude modulation is one of the oldest forms of modulation in analog communication systems, mostly due to its simplicity of

• realized with scalar operations as shown in Figure 6. The amplitude and phase are recovered by employing the output equations in Equation 4. RMS-to-DC conversion methods One of the easiest forms of amplitude estimation is RMS-to-DC conversion. The root-mean-square (RMS) value yrms of a sinusoidal signal y

• setting n = 3, which still guarantees that the component at 2fc is exactly canceled. A comparison of the original and half-period coherent demodulator is presented in Appendix B. Summary Table 1 compares the amplitude estimation techniques discussed in this section. From the classification shown in Figure