## 1 Introduction
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Paper** & \begin{tabular}{c} **Chaos** \\ **Generator** \\ \end{tabular} & \begin{tabular}{c} **ODE Discrete** \\ **Solving** \\ **Method** \\ \end{tabular} & \begin{tabular}{c} **Chaotic Syn-** \\ **chronization** \\ **Method** \\ \end{tabular} & **Modulation** & \
\begin{tabular}{c} **Passband** \\ **Method** \\ \end{tabular} &
\begin{tabular}{c} **Symbol Timing** \\ **Recovery** \\ **Method** \\ \end{tabular} & **Data Rate** \\ \hline
[10] & various & not mentioned & Hamiltonian & 16-CPSK & not present & separate signal & 20 kbps \\ \hline
[11] & van Wyk & RK-4 1 & none & DCSK- & not present & correlation & not mentioned \\ \hline
[12] & authors’ & RK-4 & not mentioned & chaotic & not present & not present & not mentioned \\ \hline
[13] &
\begin{tabular}{c} authors’, \\ nonaou- \\ digital \\ \end{tabular} & not applicable & direct coupling & chaotic encryption & not present & not present & not mentioned \\ \hline
[14] & \
\begin{tabular}{c} modified \\ [PERSON] \\ \end{tabular} & Forward Euler & Pecora-Caroll &
\begin{tabular}{c} authors’, \\ digital \\ algorithm \\ \end{tabular} & not present & not present & not mentioned \\ \hline
[15] & [PERSON] & not mentioned & \
\begin{tabular}{c} fuzzy \\ controller \\ \end{tabular} &
\begin{tabular}{c} chaotic \\ masking \\ \end{tabular} & not present & not present & not mentioned \\ \hline
[16] & authors’ & [PERSON] & Hamiltonian & \
\begin{tabular}{c} chaotic \\ masking \\ \end{tabular} & not present & separate signal &
\begin{tabular}{c} not \\ channel \\ \end{tabular} & mentioned \\ \hline
[17] & \
\begin{tabular}{c} authors’ and \\ [PERSON] \\ \end{tabular} & not mentioned & none & COOK 3 & not present & correlation &
\begin{tabular}{c} not \\ mentioned \\ \end{tabular} \\ \hline
[18] & [PERSON] & [PERSON] & Pecora-Caroll &
\begin{tabular}{c} chaotic \\ masking \\ \end{tabular} & not present & not present & not mentioned \\ \hline
[19] & [PERSON] & \begin{tabular}{c} [PERSON], \\ trapezoidal, \\ RK-4 \\ \end{tabular} & \
\begin{tabular}{c} [PERSON], \\ [PERSON], \\ OPCL 2 \\ \end{tabular} &
[20] & authors’ & [PERSON] & [PERSON] & \begin{tabular}{c} chaotic \\ masking \\ \end{tabular} & not present & not present & not mentioned \\ \hline present & \begin{tabular}{c} modified \\ [PERSON] \\ \end{tabular} & [PERSON] & \
\begin{tabular}{c} error linear \\ feedback \\ \end{tabular} & FM-ASCK & FM &
\begin{tabular}{c} modified \\ early–late gate \\ \end{tabular} & 6.1 kbps \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Overview of design features in FPGA-based chaotic communication systems. while providing improved control over signal bandwidth and maintaining a constant envelope [22]. This work builds upon our previous research [21], which introduces an ACSK-based chaotic digital communication system model implemented on an FPGA. The present study incorporates significant modifications and additions, including frequency modulation and a complete FPGA experimental setup, to advance the system's performance and verification capabilities. The novelty of the proposed FM-ACSK system lies in its effective combination of frequency modulation with the unique properties of chaotic signals, which is an underexplored area in science. Implemented on an FPGA platform, the system delivers high-speed processing and flexibility for reconfiguration. Additionally, a validated Simulink mathematical model of the system's digital components was developed to facilitate performance comparisons between the FPGA prototype and the system's simulation. The proposed system is designed as a proof-of-concept, demonstrating its feasibility for enhancing the security of the physical layer in IoT and wireless communication networks. The performance of the prototype and Simulink model is evaluated, with the system's noise immunity assessed in an additive white Gaussian noise (AWGN) channel using bit error rate (BER) analysis.