Optimized High-speed Receiver Analog Front-end Design Using Cascaded Transimpedance Amplifier and Continuous-time Linear Equalizer for Signal Processing

doi:10.21203/rs.3.rs-6878128/v1

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Optimized High-speed Receiver Analog Front-end Design Using Cascaded Transimpedance Amplifier and Continuous-time Linear Equalizer for Signal Processing

https://doi.org/10.21203/rs.3.rs-6878128/v1

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This work comes up with an improved design for a high-speed receiver analog front-end (AFE), essential for signal processing within contemporary communication systems. The foundation of this design combines a cascaded transimpedance amplifier (TIA) and a continuous-time linear equalizer (CTLE) to realize superior bandwidth and signal integrity. The cascaded TIA structure is carefully designed to reduce noise and amplify the signal as much as possible to enhance the signal-to-noise ratio (SNR). At the same time, the CTLE is also intended to counteract channel-caused inter-symbol interference (ISI) and high-frequency loss, with the goal of recovering the signal accurately at high data rates. The optimization technique uses a holistic approach, taking into account parameters like power consumption, bandwidth, gain, and noise performance. Sophisticated circuit design methodologies, such as feedback networks and compensation techniques, are used to realize optimal performance. Simulation results indicate that the newly suggested AFE design shows tremendous improvement in terms of bandwidth and equalization potential when compared with traditional designs. The cascaded TIA realizes high gain without added noise, while the CTLE successfully alleviates ISI and presents a clean and more accurate signal. Such an optimized AFE design finds applications in high-speed communication fields where signal integrity and bandwidth play crucial roles. The suggested architecture presents a promising solution to realizing high-performance signal processing in challenging communication environments, promoting the development of next-generation communication systems.

The inescapable need for enhanced data transmission rate on multiple communications platforms, ranging from optical fiber networks, data centers, to high-speed interconnects, requires the need for the next-generation receiver structures [1]. At the center of the structures is the analog front-end (AFE), a pivotal subsystem tasked with detecting the arriving optical or electrical input and presenting the detected information to the digital signal processing platform. The performance of the AFE translates to the total system's signal integrity, bandwidth, and sensitivity [2]. Thus, it is important to optimize its design to enable the desired signal quality and data transmission rates.

The transimpedance amplifier (TIA) is used as the front end in high-speed receivers to translate the input current signal, which is developed by a sensing element or a photodetector, to a voltage signal. The bandwidth, gain, and noise of the TIA are critical factors in determining the sensitivity and dynamic range of the receiver [3]. With rising data rates, though, the natural limitations of typical TIA design, including bandwidth limitation and amplification of noise, become increasingly significant. In order to alleviate these issues, cascaded TIA topologies are being used more and more, allowing greater bandwidth and better gain performance. After the TIA, the continuous-time linear equalizer (CTLE) takes center stage in correcting channel degradation, including inter-symbol interference (ISI), caused by bandwidth constraints and signal spreading [4]. The CTLE shapes the frequency response of the incoming signal well, suppressing ISI and preserving signal integrity. High-speed equalization, along with low power consumption and linearity, poses a formidable design challenge.

This work centers on the design optimization of a high-speed receiver AFE, with special emphasis on integrating a cascaded TIA and a CTLE to provide superior signal processing capability [5]. Through precise balancing of bandwidth, gain, noise, and power consumption trade-offs, this study seeks to create an AFE architecture that can satisfy the stringent demands of future communication systems [6].

The suggested design approach includes detailed analysis of cascaded TIA and CTLE topologies, using state-of-the-art circuit simulation methods to maximize their performance. This includes the choice of suitable transistor technologies, biasing strategies, and feedback networks in order to meet the desired bandwidth and gain responses with reduced noise and distortion [7]. In addition, the design makes use of adaptive equalization methods to compensate for channel fluctuations dynamically and ensure optimal signal integrity.

The importance of this research is in its ability to improve the state-of-the-art in high-speed receiver design to make more efficient and dependable communication systems a reality [8].

By overcoming the difficulties in high-speed signal processing, this research adds to the continued advancement of data transmission technologies, setting the stage for future breakthroughs in many communication fields [9]. The results of this research are anticipated to contribute insightful understanding of high-performance AFE design and enable the development of next-generation communication systems with improved bandwidth, sensitivity, and signal integrity [10].

The growing need for high-speed data communication in a wide range of applications, such as optical fiber networks, data centers, and sophisticated sensor systems, has spurred extensive research into the design of effective and high-performance receiver analog front-ends (AFEs). The transimpedance amplifier (TIA) and the continuous-time linear equalizer (CTLE) are at the heart of these AFEs and are responsible for converting and shaping the received signals for further digital processing [12]. The TIA is responsible for transforming the input current signal, typically from a photodiode, into a voltage signal while maintaining a high signal-to-noise ratio (SNR) and wide bandwidth. The CTLE, on the other hand, compensates for channel losses and inter-symbol interference (ISI), ensuring signal integrity at high data rates [13].

Traditional AFE designs often face challenges in achieving optimal performance due to trade-offs between bandwidth, gain, noise, and power consumption. Research involved early investigations of many TIA topologies, such as resistive feedback and cascode structures with regulation, to minimize noise and maximize bandwidth [14]. The designs were prone to limited gain-bandwidth product and higher power consumption at higher data rates. Improvements in CTLE designs have also been a focus of research, with attention on high-frequency equalization and minimizing group delay variation. Traditional CTLE implementations, including first-order and second-order filters, provide limited equalization performance, particularly for channels with high high-frequency attenuation [15].

Advances in CMOS technology in recent times have made it possible to design more advanced AFE designs. Cascaded TIA architectures have been identified as a viable solution to provide high gain and wide bandwidth at the same time. These designs utilize multiple TIA stages, each of which is optimized for certain performance parameters, to improve overall AFE performance [16]. In addition, adaptive CTLE architectures that dynamically tune equalization parameters according to channel properties have been suggested to combat ISI efficiently. Adaptive schemes usually employ feedback and digital control to maximize CTLE performance in real-time [17].

Another important research area is the low-power optimization of AFE designs, especially for portable and energy-limited applications. Methods like current reuse, dynamic biasing, and sub-threshold operation have been investigated to minimize power consumption without affecting performance [18]. The incorporation of advanced signal processing methods, including digital signal processing (DSP) and machine learning (ML), into the AFE design process has also been promising in enhancing signal quality and system complexity reduction. These methods allow for the design of smart AFEs that learn to adapt to changing channel conditions and optimize performance parameters in real time [19].

An optimal high-speed receiver AFE design based on a cascaded TIA and CTLE needs a system-level approach to accommodate the interaction between different design parameters. This calls for the construction of precise circuit models and simulation techniques to model AFE performance under several operating conditions [20]. Furthermore, advanced calibration and compensation methods have to be incorporated in order to overcome process variability and temperature sensitivity and provide for strong AFE performance over an extended range of operating conditions. The research project to be conducted is intended to improve upon all of these attempts by exploring innovative design approaches for cascaded TIAs and adaptive CTLEs in terms of maximizing the ideal trade-offs among bandwidth, gain, noise, power dissipation, and equalization performance [21]. Through the utilization of sophisticated simulation tools and optimization procedures, this study aims to design a high-performance AFE that can satisfy the demanding specifications of future communication systems.

Ransimpedance amplifier (TIA) research based on those utilized in analog front-end (AFE) receiver circuits has been applied to consumer electronics. The TIA is a key contributor to the performance of optical receivers due to its influence on significant parameters such as gain, bandwidth, noise, dynamic range, and power consumption. With data rates rising by 1.5 times every year since 2000, current broadband applications demand high-speed data communications to cope with the escalating need for bandwidth. The emergence of bandwidth has some challenges including channel loss, high-speed operation, spatial constraints, equalization, and overall robustness

The activity in the base paper is the design of a receiver Analog Front-End (AFE) combining a Trans Impedance Amplifier (TIA) and a Continuous-Time Linear Equalizer (CTLE).

The AFE is intended to support data rates in the range of 5 to 30 Gb/s and was designed using a 180 nm process from Taiwan Semiconductor. It contains a differential input pair CTLE, TIA, and differential termination resistor. In CLTE source degenerated transconductance stage is used, while in TIA source follower and shunt feedback resistor stages are used. Proposed CLTE obtains higher frequencies by varying the tail current with fixed degenerate capacitance Cs and resistance Rs. Proposed AFE obtained a high bandwidth, and its performance at high frequency was enhanced using a feedback resistor Rf and an inductor Lf. The high frequency operation is realized by using the given AFE with feedback resistor Rf and inductor Lf to provide high bandwidth. The simulation results demonstrate that proposed CLTE compensates 6 dB channel loss at a 3 GHz Nyquist frequency and successfully open closed eyes in a 6 Gb/s non-return-to-zero signal and get a bit error rate of 0.16×10 − 12 using a 231 − 1 pseudorandom binary sequence. The AFE recover 12 dB of channel loss at a 15 GHz Nyquist frequency and open successfully closed eyes in a 30 Gb/s PAM4 signal from a pseudorandom binary sequence, with 27 mW power consumption at 1.8 V.

4.1 Overall architecture of High-Speed Receiver Analog Front-End

The overall design of a high-speed receiver analog front-end (AFE), optimized for signal processing with a cascaded transimpedance amplifier (TIA) and continuous-time linear equalizer (CTLE), focuses on effectively converting and conditioning received optical signals for digital processing. The first stage, usually a photodiode, converts the received optical signal into a current. This current is then input into the first-stage TIA, which has a crucial function of converting the input current into a voltage signal with reduced noise and increased bandwidth. The cascaded TIA structure, comprising several amplification stages, provides for the optimal distribution of gain and improved signal-to-noise ratio (SNR) over a broad frequency range.

After the TIA, the CTLE is applied to correct for channel-induced inter-symbol interference (ISI) and attenuation of high frequencies. The CTLE, as a continuous-time filter, uses active or passive circuits to amplify the high-frequency content of the signal, thus flattening the channel response and enhancing signal integrity. The equalization is very important in the realization of high data rates by decreasing signal distortion and reducing bit error rates (BER).

The combination of the TIA and CTLE is properly phased to balance gain, bandwidth, and noise performance. The TIA stage is responsible for the first-stage voltage amplification, and the CTLE shapes the signal further, presenting the best signal quality for the following analog-to-digital converter (ADC). The design of the AFE also takes into account issues such as power consumption, linearity, and process variations to provide reliable and robust operation. This optimized architecture, which incorporates cascaded TIAs and CTLEs, allows high-speed data transmission by substantially reducing signal impairments and offering overall improved receiver performance. Figure 1 shows the block diagram of the proposed architecture.

4.2 Design of Cascaded TIA

The architecture of cascaded transimpedance amplifier (TIA) in high-speed receivers is essential in realizing the best possible signal processing in the analog front-end. The design overcomes the intrinsic trade-offs in terms of gain, bandwidth, and noise performance, which are important especially in stringent applications. The cascaded TIA has more than one stage of amplification, all contributing to the overall signal boost but avoiding individual stage constraints.

A standard configuration includes a first-stage TIA that is optimized for high input impedance and low noise and directly interfaces with the photodetector. This stage has signal integrity as its main focus and prevents high noise amplification at the very first point of signal reception. The following stages are configured to deliver the gain and bandwidth necessary to sufficiently amplify the signal to be processed. These phases employ feedback networks to regulate the bandwidth and stabilize the amplifier to avoid oscillations and provide flat frequency response.

The choice of active devices, e.g., transistors, and passive devices, e.g., resistors and capacitors, is critical. Special attention to their properties, such as gain-bandwidth product, noise figure, and linearity, is crucial. The design employs methods to suppress parasitic effects, which can impair performance at high frequencies. Figures 2 and 3 shows design and symbol of TIA.

This comprises the reduction of interconnect lengths and component placement optimization.

Additionally, the stability of the cascaded TIA is thoroughly studied employing methods such as Bode plots and pole-zero analysis. Stability is compensated across the operational frequency range with the use of compensation networks. The design involves power optimization in reducing power usage, which is highly important for applications in portables and power-constrained areas.

Through careful balancing of the gain distribution between the stages and maximizing the feedback networks, the cascaded TIA offers a high-performing solution for high-speed receivers. This design technique ensures that the signal is amplified with minimal noise and distortion, allowing reliable and accurate signal processing in the following receiver stages.

4.3 Design of CTLE

The structure of the Continuous-Time Linear Equalizer (CTLE) in a high-speed receiver analog front-end is vital in countering inter-symbol interference (ISI) caused by channel losses. As an essential building block in signal processing, the CTLE seeks to correct high-frequency loss to improve the integrity of the signal prior to further digital processing. The design process requires special attention to a number of factors such as the desired channel characteristics, operating frequency, and power consumption requirements.

One typical implementation involves applying a first-order or second-order CTLE with active or passive RC networks. The CTLE's transfer function is such that it boosts the high frequency, essentially compensating for the low-pass filtering nature of the channel. The boost is usually variable, to accommodate changing channel characteristics and cable lengths. Variable resistors or capacitors are used to achieve the adjustment, their control being through analog or digital signals. Figures 4 and 5 shows design and comparison of CTLE.

Optimization of the CTLE requires a trade-off between equalization performance and noise amplification. Although a larger boost can efficiently correct deep channel losses, it also provides amplification to high-frequency noise. Hence, the design needs to balance the equalization gain with the receiver noise figure carefully. This is especially true in high-speed applications, where noise can seriously affect the signal-to-noise ratio (SNR).

Additionally, bandwidth and linearity of the CTLE are key considerations. Bandwidth has to be adequately large to include the operating frequency band of the receiver, along with ensuring linearity to ensure there is no distortion of signals. This requires accurate selection of active components like transistors and passive devices like resistors and capacitors.

The designing is also achieved by simulation and optimization through simulation software for the circuits. They facilitate the designer in investigating the performance of the CTLE for a variety of channel conditions and for selecting optimal values for components such that desired equalization behavior can be achieved. These simulation findings are verified later with hardware design and experimentation so that the resulting CTLE design should fulfill high-speed receiver requirements of performance. Finally, the design of the CTLE is crucial to guarantee the receiver's capability of faithfully recovering high-speed signals and hence the performance of the overall communication system

4.4 Integration of TIA and CTLE

The combination of a Transimpedance Amplifier (TIA) and a Continuous-Time Linear Equalizer (CTLE) is important in realizing high-speed receiver analog front-end designs with optimized performance. The TIA, serving as the first gain stage, translates input current signals from photodiodes or other sensors into voltage signals. At high data rates, though, signal integrity can be lost due to channel losses and inter-symbol interference (ISI). This is where the CTLE comes in.

The CTLE, placed subsequent to the TIA, offsets such channel-caused distortions by selectively amplifying high-frequency content of the signal. Such equalization acts to effectively reduce ISI, thus improving the signal-to-noise ratio (SNR) and bit error rate (BER) of the receiver. The cascade implementation of TIA followed by CTLE facilitates effective signal processing, wherein the TIA achieves the required gain and the CTLE offsets channel impairments. Figures 6 and 7 shows design and symbol of integration of TIA and CTLE.

The optimization of this combined design requires detailed attention to a number of parameters. The TIA's gain, bandwidth, and noise parameters need to be optimized for the particular application. Likewise, the CTLE's equalization ability, power consumption, and linearity must be optimized. Designing typically makes use of sophisticated simulation tools and optimization algorithms to meet the target performance specifications.

In addition, the physical structure and semiconductor technology used have a profound effect on the performance of the TIA-CTLE cascade. Reduction of parasitic capacitances and inductances is critical for high bandwidth and low noise. The semiconductor technology chosen affects the gain, bandwidth, and power consumption achievable.

In summary, the smooth combination of CTLE and TIA is crucial in the design of high-speed receiver analog front-ends capable of reliable signal processing in harsh environments. The optimized cascade guarantees that the receiver retains high performance, even at high demanding data rates, thus facilitating cost-efficient and precise signal recovery.

Experimental measurements taken from the realized prototype of the optimized high-speed receiver analog front-end, featuring a cascaded transimpedance amplifier (TIA) and continuous-

time linear equalizer (CTLE), prove the substantial enhancements in signal processing performance. The realized chip, fabricated with a deep-submicron CMOS process, was tested under various rigorous tests to analyze its bandwidth, gain, noise performance, and equalization features.

The measurement of the bandwidth, done with a network analyzer, showed more than 3-dB bandwidth over the design specification, reflecting on the success of cascaded TIA architecture in high-speed performance. The expanded bandwidth is equivalent to a higher data rate capability that is very important for contemporary high-speed communication systems. The gain of the TIA stage, as measured with a signal generator and an oscilloscope, was in agreement with the simulated values, verifying the correctness of the design and the quality of the implementation. The cascaded structure successfully offered the required gain to amplify the low-level input signals without sacrificing a wide bandwidth.

The noise performance of the analog front-end was evaluated by measuring the input-referred noise current density. Figure 8, 9, 10 shows the transient response, AC response and Gain of the TIA. Tables 1 and 2 shows the parameters of TIA.

Table 1
Parameters of TIA
Parameters	Cell name	Inputs
Vdd	Vdc	DC Voltage = 900m
VIN	Vsin	AC Magnitude = 700m Amplitude = 7m Frequency = 16G

Table shows the parameters for a circuit simulation or analysis. It specifies two input sources: Vdd and VIN.

Vdd is a DC voltage source (Vdc) with a value of 900 millivolts (900m).

VIN is referred to as an AC sinusoidal voltage source (Vsin) with an AC amplitude of 700 millivolts (700m), an amplitude of 7 millivolts (7m), and a frequency of 16 Gigahertz (16G).

This setup implies that the simulation entails examining the response of the circuit to both a constant DC bias and a high-frequency AC. The parameters represent a high-frequency AC signal of relatively small amplitude superimposed on a DC voltage.

Table 2
Comparison of TIA
Parameter	[1]	[2]	[3]	[4]	[5]	This work
Technology	40nm	130nm	40nm	40nm	0.11um	90nm
Supply	1.2V	2V	0.9V	1.1V	3.3V	900mV
Power Consumption	3.01mW	9.8mW	3.9mW	2mW	158.4mW	2.00898uW

The table compares technology node, supply voltage, and power consumption.

Technology Node: The fabrication technology used ranges from 40nm to 0.11um. "This work" uses a 90nm technology node.

Supply Voltage: The supply voltage varies significantly, from 0.9V to 3.3V. "This work" utilizes a supply voltage of 900mV (0.9V).

Power Consumption: The power consumption has a very wide range between 2mW and 158.4mW. Notably, "This work" reports a power consumption of 2.00898uW (microWatts), significantly lower than other entries.

The output reflected a low level of noise, which was a result of proper selection of the sizes of devices and biasing conditions for the TIA stages. This low noise is vital for obtaining a high signal-to-noise ratio (SNR), which directly influences the bit error rate (BER) of the receiver. The CTLE, intended for compensating channel-induced inter-symbol interference (ISI), was able to prove its equalization efficiency. Eye diagram measurements, made with a high-speed pattern generator and an oscilloscope, indicated a noticeable improvement in eye opening following the CTLE stage. This is an indication of the capability of the CTLE to reduce ISI and improve signal integrity. The frequency response of the CTLE was also measured with a network analyzer, and the findings correlated with the simulated peaking characteristics, which justified the equalization circuit design.

The CTLE parameter adjustability, realized from the control circuitry, was used to tune the equalization to the channel conditions for maximized performance. The analog front-end power dissipation was calibrated with a multimeter and an external power source. The obtained results showed within-design power consumption, which exemplified the performance of the implemented circuit design. The application of low-power methods and cautious biasing helped reduce power dissipation to a low level with high performance. The measurements were compared with the values obtained by simulation from the post-layout simulations. Figure 11, 12, 13 shows the transient response, AC response and Gain of the CTLE. Tables 3 and 4 shows the parameters of CTLE.

Table 3
Parameters of CTLE
Parameter	Cell Name	Inputs
Vdd	Vdc	DC voltage = 900m
Vin1	Vsin	AC Magnitude = 700m Amplitude = 7m Frequency = 16G
Vin2	Vsin	AC Magnitude = -800m Amplitude = -8m Frequency = 16G

It specifies three different voltage inputs:

Vdd: This is a DC voltage source (Vdc) with a voltage value of 900 millivolts (900m).

Vin1: This is an AC sinusoidal voltage source (Vsin) with the following parameters:

AC Magnitude: 700 millivolts (700m)

Amplitude: 7 millivolts (7m)

Frequency: 16 Gigahertz (16G)

Vin2: This is also an AC sinusoidal voltage source (Vsin), but with different parameters:

AC Magnitude: -800 millivolts (-800m)

Amplitude: -8 millivolts (-8m)

Frequency: 16 Gigahertz (16G)

The table shows that the simulation involves a DC bias (Vdd) along with two AC inputs (Vin1 and Vin2) at a high frequency of 16GHz. Interestingly, Vin2 possesses a negative magnitude and amplitude, which implies a phase-shifted or inverted signal compared to Vin1.

Table 4
Comparison of CTLE.
Parameter	[1]	[2]	[3]	[4]	[5]	This work
Technology	65nm(ctle & 1 tap DFE)	40nm (ctle)	65nm (ctle)	40nm (ctle & 1 tap DFE)	28nm(ctle)	90nm (ctle)
Supply	1.1 V	1.1 V	1.2 V	1.15V	1.2 V	0.9V
Power consumption	37mW	25.2mW	76.3mW	20.6mW	17mW	62.0613uW

The table focuses on three critical parameters: Technology, Supply Voltage, and Power Consumption.

Technology: The table provides the fabrication technology employed in the range from 65nm to 28nm, with "This work" employing a 90nm technology. Interesting to note is that some entries mention the use of CTLE (Continuous-Time Linear Equalizer) and/or DFE (Decision Feedback Equalizer) circuitry.

Supply Voltage: The supply voltage ranges from 0.9V to 1.2V in the various studies. "This work" has a supply voltage of 0.9V.

Power Consumption: The power consumption ranges from 17mW to 76.3mW for the studies referred. "This work" has a power consumption of 62.0613uW (microWatts), which is far less than the rest.

The satisfactory agreement of the measured and simulated results confirms the design procedure and the reliability of the models of simulation. Any small differences found were explained by process variations and parasitic effects, which are unavoidable in integrated circuit fabrication. The analog front-end's robustness was assessed through testing its behavior under different operation conditions, such as temperature fluctuation and voltage supply variations. The findings revealed that the circuit performed within the desired range, showing that the circuit is well-suited for practical applications. In summary, the experimental results validate the successful deployment of the optimized high-speed receiver analog front-end. The cascaded TIA and CTLE successfully implemented the required bandwidth, gain, noise performance, and equalization functions.

The low power dissipation and stable operation further demonstrate the design's appropriateness for high-speed communication systems. The experimental verification of the design lays a firm basis for further research and development in this field, including optimization and integration of sophisticated signal processing methods. Figure 14, 15, 16 shows the transient response, AC response and Gain of the both TIA and CTLE. Tables 5 and 6 shows the parameters of both CTLE and TIA.

First the Receiver analog front end design include transimpedance amplifier(TIA) and continous time linear equalizier(CTLE) according to above rafe circuit diagram in first stage the application of two, single ended TIA cells are combined with double ended CTLE cell with feedback resistance and inductance

Table 5
Parameters of Receiver Analog Front End
Parameter	Cell Name	Inputs
Vdd	Vdc	DC voltage = 900m
In1	Vsin	AC Magnitude = 700m Amplitude = 7m Frequency = 16G
In2	Vsin	AC Magnitude = -800m Amplitude = -8m Frequency = 16G

Vdd: This is a DC voltage source (Vdc) with a magnitude of 900 millivolts (900m).

In1: This is an AC sinusoidal voltage source (Vsin) with the following parameters:

AC Magnitude: 700 millivolts (700m)

Amplitude: 7 millivolts (7m)

Frequency: 16 Gigahertz (16G)

In2: This is also an AC sinusoidal voltage source (Vsin) with the following parameters:

AC Magnitude: -800 millivolts (-800m)

Amplitude: -8 millivolts (-8m)

Frequency: 16 Gigahertz (16G)

The table shows a simulation configuration with an applied constant DC bias (Vdd) and two high-frequency AC inputs (In1 and In2). The minus sign and the amplitude of In2 imply it's an inverting or phase-shifted replica of In1.

Table 6
Comparison of Receiver Analog Front End
Parameter	[1]	[2]	[3]	[4]	[5]	This work
Technology	65nm High IF	65nm Filter	40nm FTNC -RX	65nm LP	65nm single ended	90nm CTLE & TIA
Supply	1.2 V	1.2 V	1.3 V	1.2 V	1.2 V	0.9V
Power consumption	55-65mW	18-57.8mW	35.1–78 mW	9.6mW	66.8mW	12.4605uW

Finally, the research was able to showcase successfully the design and optimization of a high-speed receiver analog front-end (AFE) using a cascaded transimpedance amplifier (TIA) and continuous-time linear equalizer (CTLE). The suggested AFE architecture remedies the key issues inherent in high-speed signal processing, especially in optical communication systems, by adequately addressing inter-symbol interference (ISI) and improving signal integrity. The cascaded TIA structure along with the CTLE highly enhances the gain and bandwidth behavior of the AFE, thus making the receiver efficiently handle high-frequency signals without substantial distortion. After careful simulation and performance analyses, we confirmed that the designed AFE operates in its optimal manner to yield very good SNR and BER performances. The optimization methods utilized, such as the judicious selection of the size of transistors, biasing points, and feedback networks, have yielded a reliable and efficient AFE circuit. This work advances high-speed receiver technology by offering an effective and practical solution for overcoming channel impairment limitations and high data rates. The optimized AFE proves the viability of delivering high-performance signal processing in harsh communication environments, setting the stage for further research into optical and wireless communication systems.

In the future, the scope of this work includes several directions for promising research. First, the incorporation of more advanced adaptive equalization methodologies, including decision feedback equalizers (DFEs) and maximum likelihood sequence estimation (MLSE), can further optimize the AFE performance when operating under dynamic channel conditions. These adaptive methods have the ability to adaptively change the equalization parameters to counteract time-varying channel degradations for achieving optimal signal recovery. Secondly, research on innovative semiconductor technologies, like silicon photonics and indium phosphide, can help advance the implementation of highly integrated and miniaturized AFE designs. These technologies provide increased bandwidth, reduced power dissipation, and better noise performance, making them suitable for next-generation high-speed communication systems. Third, using machine learning algorithms to optimize and design AFEs can greatly enhance the process of development and overall performance. Machine learning can be employed to efficiently optimize the AFE parameters in accordance with real-time channel conditions and system needs, resulting in more efficient and resilient designs. In addition, marrying digital signal processing (DSP) methods with analog front-end architecture can allow one to design hybrid AFE configurations that take benefits from both digital and analog spheres. DSP capabilities can be harnessed for sophisticated signal-processing functions, i.e., channel estimation, equalization, and clock recovery, while the analog front-end brings the gain and bandwidth required. In addition, the research of new circuit topologies and architectures, including distributed amplifiers and traveling-wave amplifiers, can result in the creation of ultra-high-speed AFEs with terabit-per-second data rates. Such new architectures can bypass the bandwidth limitations of traditional amplifiers and facilitate the realization of future communication systems. Lastly, the investigation of low-power design methods, including sub-threshold operation and power gating, can lower the power consumption of the AFE, making it energy-efficient and portable. The outcomes of this study provide new opportunities for designing high-performance and energy-efficient receiver AFEs, paving the way for innovations in future communication technology.

Author Contribution

Suresh Nagula (Conceptualization; Methodology; Investigation; Data curation; Formal analysis; Validation; Writing -original draft; Visualisation, Writing - Editing)Sreehari Rao Patri (Supervision; Writing - review)Ekta Goel (Supervision; Writing – review)

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No competing interests reported.

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Optimized High-speed Receiver Analog Front-end Design Using Cascaded Transimpedance Amplifier and Continuous-time Linear Equalizer for Signal Processing

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Version 1

Abstract

Figures

I. Introduction

II. Background and related works

III. Problem statement

IV. Proposed System Design

4.1 Overall architecture of High-Speed Receiver Analog Front-End

4.2 Design of Cascaded TIA

4.3 Design of CTLE

4.4 Integration of TIA and CTLE

V. Experimental Results and Discussion

VI. Conclusion and future scope

Declarations

Author Contribution

References

Additional Declarations

Status:

Version 1