# Design and Development of an SVM-Powered Underwater Acoustic Modem
## 3 Results
### Performance Analysis  
This section delineates the performance metrics of the developed SVM-powered underwater modern system, with a focus on its demodulation capabilities. Through rigorous experimentation, the system demonstrated very good performance in terms of  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Fold 1** & **Fold 2** & **Fold 3** & **Fold 4** & **Fold 5** & **Fold 6** & **Fold 7** & **Fold 8** & **Fold 9** & **Fold 10** \\ \hline
1.0000 & 1.0000 & 1.0000 & 1.0000 & 1.0000 & 1.0000 & 1.0000 & 1.0000 & 1.0000 & 0.9980 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Accuracy for each fold in the K-fold cross-validation process.  
Figure 7: Scalograms for low (10) and high (35) numbers of voices per octave. (**a**) Scalogram for VPO = 10. (**b**) Scalogram for VPO = 35.  
signal classification accuracy, robustness in various noise conditions, and a consistent demodulation bitrate, which are critical factors for effective underwater communication.
* Accuracy and robustness: The demodulation process accuracy was evaluated across a spectrum of SNR levels, with the model exhibiting an impressive accuracy of 98.28%, even at a low SNR of 5 dB. As the SNR increased, the accuracy ascended, peaking at 99.78% for SNRs of 23, 24, and 25 dB, indicating the high fidelity of the system in signal reconstruction under diverse noise conditions. This robustness is crucial, as it directly relates to a lower bit error rate (BER), which is a key determinant of the demodulation success in real-world underwater communication systems.
* Precision and recall: The precision and recall metrics further substantiate the demodulation efficacy. Precision quantifies the proportion of true positives against all positive predictions, and recall measures the proportion of true positives identified correctly. At the highest tested SNR of 25 dB, the precision and recall for class \"\(1\)\" were 99.79% and 99.39%, respectively, and for class \"\(0\)\", both metrics were 99.90%. These high values suggest that the system correctly demodulated the FSK signals, which is indicative of an extremely low BER, and thus, high data integrity.
* Demodulation bitrate: beyond these classification metrics, the system achieved a stable and consistent demodulation bitrate of 10,000 bauds.  
Beyond the metrics of precision and recall, the main point of the demodulation strategy hinges on the unique processing of symbols, where each \"\(1\)\" or \"\(0\)\" and the transitional \"C\" symbol was distinctly represented by 100 digitized samples. This precise sample-based representation facilitated an accurate symbol identification and boundary delineation process. By systematically analyzing the output from the SVM, which decided the start and end points of each symbol, the system ensured that the integrity of the transmitted data was maintained. As a result, a demodulation bitrate of 10,000 bauds was achieved, with the final demodulated symbols reflecting a BER of zero. This outcome not only validated the robustness of the SVM-powered modem but also possibly set a new standard in the fidelity of underwater communication systems. This zero BER is a testament to the precision achieved, confirming the system capability to deliver flawless data transmission under controlled experimental conditions.