## 6 Simulation Results
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Harmonic Number** & **Frequency (MHz)** & **Fourier Component** & **Phase (degree)** \\ \hline
1 & 2.122 & 17.5810 u & \(-\)27.9532 \\
2 & 4.244 & 175.7963 n & \(-\)143.2494 \\
3 & 6.366 & 204.1361 n & 155.1108 \\
4 & 8.488 & 57.0393 n & 145.0789 \\
5 & 10.610 & 12.1911 n & \(-\)93.1991 \\
6 & 12.732 & 162.208 n & \(-\)141.3161 \\
7 & 14.854 & 6.6238 n & 157.6872 \\
8 & 16.976 & 10.0840 n & 161.5075 \\
9 & 19.098 & 13.2706 n & \(-\)179.8498 \\  & \multicolumn{3}{c}{DC component = \(-\)2.993 x 10\({}^{-8}\)} \\  & \multicolumn{3}{c}{Total harmonic distortion = 1.5739\%} \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Total harmonic distortion analysis of \(I_{01}\) in Figure 3. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Harmonic Number** & **Frequency (MHz)** & **Fourier Component** & **Phase (degree)** \\ \hline
1 & 2.122 & 17.2823 u & \(-\)117.8809 \\
2 & 4.244 & 72.1321 n & 106.2341 \\
3 & 6.366 & 156.5673 n & 26.8057 \\
4 & 8.488 & 24.1643 n & 25.9664 \\
5 & 10.610 & 8.2084 n & 1.3462 \\
6 & 12.732 & 7.7736 n & 16.4662 \\
7 & 14.854 & 8.5334 n & 8.0360 \\
8 & 16.976 & 7.4771 n & 11.0721 \\
9 & 19.098 & 6.5087 n & 14.8607 \\  & \multicolumn{3}{c}{DC component = \(-\)5.366 x 10\({}^{-8}\)} \\  & \multicolumn{3}{c}{Total harmonic distortion = 1.0122\%} \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Total harmonic distortion analysis of \(I_{02}\) in Figure 3.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Harmonic Number** & **Frequency (MHz)** & **Fourier Component** & **Phase (degree)** \\ \hline
1 & 2.122 & 131.6570 m & 152.1558 \\
2 & 4.244 & 1.7963 m & \(-\)145.6957 \\
3 & 6.366 & 1.3875 m & \(-\)16.7744 \\
4 & 8.488 & 280.3543 u & \(-\)35.0773 \\
5 & 10.610 & 59.7716 u & \(-\)158.4953 \\
6 and the operational transconductance amplifiers of MAX435 and CA3080. The DC power supply voltages are \(\pm\)5 V. The \(g_{m}\)-value of the MAX435 is equal to \(4/R_{g}\), where \(R_{g}\) is an external resistor [36]. In general, the applicability of such current-feedback operational amplifier (CFOA)-based oscillators is usually limited to a few hundred kilohertz [37; 38]. Figure 13 shows the experimental result of the frequency range of a commercially available AD844 with \(\pm\)5 V DC supply. In Figure 13, the values of the resistors were chosen as \(R_{1}=R_{2}=1\) k\(\Omega\) (5 k\(\Omega\), 10 k\(\Omega\)), \(R_{L}=500\)\(\Omega\), \(C_{L}=10\) pF, and the input power was 0 dBm. Figure 14 is the measured result of a spectrum analyzer, which shows that the measured result of the frequency range of AD844 was limited to 2 MHz. The passive component values of the circuit in Figure 12 were set as \(g_{m1}=1.428\) mS (i.e., \(R_{g}=2.8\) k\(\Omega\)), \(R_{X1}=0.73\) k\(\Omega\), \(R_{X2}=0.7\) k\(\Omega\), \(R=1\) k\(\Omega\) and \(C_{1}=C_{2}=C_{3}=750\) pF, where \(R_{X1}\) was designed to be larger than the theoretical value to ensure that the oscillator will start, before the centre frequency was obtained as \(f_{o}=303.15\) kHz. The oscilloscope output waveforms, \(V_{o1}\) and \(V_{o2}\), of the proposed oscillator are shown in Figure 15, and the \(X\)-\(Y\) plot of \(V_{o1}\) and \(V_{o2}\) output voltages are shown in Figure 16. The experimental oscillation frequency in Figure 15 is 295.2 kHz, which is close to the theoretical value of 303.15 kHz with a 2.62% error rate. Figures 17-19 show the AM and the ASK signal outputs of the quadrature oscillator, where the modulation signal, \(I_{B2}\), applied a sinusoidal signal, a triangular signal, or a pulse signal with a 30-kHz frequency. The experimental results are close to the theoretical analysis of Equation (12). Figure 12: A possible implement method of the proposed oscillator by using commercially available ICs. Figure 13: Tested frequency range of AD844.