Abstract—In voice communications, the speech signal is degraded when gone through the system layers, since the best effort arrangement based IP network prompts the system degradations including Silence, packet loss jitter. This paper represents the impact system debasement calculates on VoIP system and the otherworldly analysis of the VoIP signal. The spectral analysis of VoIP signal is performed through the various signal processing algorithms. The outcomes are accepted through the quality assessment of the VoIP signal utilizing perceptual evolution of speech quality (PESQ) approximation for narrowband signal. For digital signal processing LTI System, an input signal can be mapped to an output signal where in mapping we can transform the signal in a manner that the voice quality can be enhanced than before extraordinarily in low bandwidth region. The mapping process can extract the noise and the resulting amplifying signal will have low SNR as compared to input signal. It can be shown that the voice bit rate can be drawn approximately to 5.3 kbps with excellent voice quality.
Index Terms—Spectrogram, SNR (signal to noise ratio), LTI (linear time-invariant), MOS (mean opinion score), FIR (Finite impulse response).
Md. N. A. Shafi and Md. Niamul Hassan are with the Network Operations Center of Inspire Systems Limited, Dhaka, Bangladesh (e-mail: nahid_apee@yahoo.com, nhleon17.nl@gmail.com).
Abdullah Al Mamun is with the TISL, Dhaka, Bangladesh (e-mail: aamamun.deb19@gmail.com).
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Cite:Md. Nahid Akter Shafi, Abdullah Al Mamun, and Md. Niamul Hassan, "An Improvement of Voice Quality in LTI System Operating in Codec G729 [ANNEXB = NO] for Low Bandwidth Region," International Journal of Computer Theory and Engineering vol. 9, no. 2, pp. 123-126, 2017.
