## 3 Results  
The proposed AFE cascading TIA and CTLE was designed and simulated in a 180 nm complementary metal-oxide-semiconductor (CMOS) process. The performance of the CTLE, TIA, and the resulting eye diagram was simulated with Virtuoso 6.1.8-64 b software. A high-frequency through-silicon scalable electrical model using a field solver was used as a transmission line (channel) [24; 25]. Figure 10 reveals that the simulated channel can achieve 10 dB decay isolation loss at a 1.5 GHz Nyquist frequency for different cable lengths (2-8 m). Figure 11 reveals that the simulated CTLE can achieve a DC gain of \(-2\) to 9 dB at a 3 GHz Nyquist frequency by tuning bias voltage \(V_{bias}\) and \(V_{bias}\) and adjusting the voltage \(V_{adjust}\) (represented by X in Figure 11) from +360 to \(-360\) mV for a channel length of 3 m. Figure 12 presents the characteristics of CTLE with and without a 3 m channel at a 3 GHz Nyquist frequency. Figure 10: Variations in Channel Characteristics for Lengths of 2 m–8 m at 1.5 GHz. Figure 13 presents the simulated single-ended 6 Gb/s NRZ eye diagrams with the two different lossy channels. Figure 13b reveals that output eye is closed at the decay stage in which the CTLE is disabled. By contrast, Figure 13a reveals that the 6 Gb/s NRZ eyes are open if the CTLE is enabled. Figure 12: Simulated AC response of the CTLE with and without the Channel. Figure 13: Simulated Output Eyes (**a**) with CTLE Enabled and (**b**) with CTLE Disabled. In this case, the input signal was a simulated NRZ pseudorandom bit sequence \(2^{31}-1\) with a peak-to-peak amplitude of 189.914 mV; the root-mean square jitter was 8.86 picosecond. An input and output impedance of 50 \(\Omega\) and a 50 pf capacitor were used in this case. Figure 14 presents all measured parameters of the simulated eye diagram. Figure 15 presents the simulated histogram plots used to calculate the eye width and height. Figure 15a presents a horizontal histogram used to measure the eye width at each time point and to sum up the number of traces across vertical bins. Figure 15b is a vertical histogram of eye height measurements for every amplitude point; these points were summed across the time axis. Simulated BER bathtub curves for NRZ input data rates of 6 Gb/s are presented in Figure 16. The BER variations for different positions of the sampling point for both time delay and the voltage-power relationship are presented in Figure 16. In this case, BER(t) was 0.16 \(\times\) 10\({}^{-12}\). Table 1 summarizes the key performance metrics of the proposed CTLE and other recently published CTLEs. The proposed CTLE achieved a peaking frequency with constant current for tuning its equalization competence. Figure 17 presents the simulated frequency response of the AFE cascading the CTLE and the TIA. Subsequently, the bandwidth must recover from 6 GHz (approximately 18/3 GHz) to 15 GHz; thus, the equalizer is tuned to its maximum peaking. To reach this required bandwidth, the TIA is designed to boost the equalizer by introducing a feedback resistor \(R_{\mathrm{s}}\) and inductor \(L_{\mathrm{f}}\). The frequency response for AFE reached 15 GHz at various bias voltages (\(-\)80, 0, and 80 mV) with 12 dB channel losses at a 15 GHz Nyquist frequency with a 3 m channel (Figure 17a). Similarly, Figure 17b reveals that the DC gain varies as \(V_{adjust}\) varied from \(-\)80 to 160 mV at a 15 GHz Nyquist frequency. Figure 14: Simulated Eye Diagram. (1) 0 level at 1.33 V; (2) 1 level at 1.52 V; (3) and (4) rise and fall time of 102.2 and 95.1151 ps, respectively; (5) and (6) eye height and width of 118.882 mV and 196.79 ps, respectively. Figure 16: Simulated BER(t) bathtub curves for the 6 Gb/s NRZ signal. Figure 15: (**a**) Horizontal Histogram and (**b**) Vertical Histogram of eye diagrams for the 0 and 1 levels.