22/09/2011

HD Voice technology, and Bluetooth cell phone headset implementation

HD Voice also known as voice over broadband, Acer aspire one Zg5 is a cellular network for mobile phones and wireless headsets transmit high-definition, natural sound quality of audio technology. Compared to traditional telephone, voice close high definition voice quality improved, reducing the burden of hearing.

The chain of the communications industry is subject to all networks and devices to support HD voice will demonstrate the Sony VGP-BPS13/Q Battery benefits of technology to. Work in June 2011, 18 countries, the mobile network 20 and 33 brands of mobile phones have a high definition audio. Using Adaptive Multi-Rate Wideband (AMR-WB) speech coding, GSM, WCDMA (UMTS) mobile networks and LTE introduces high-definition audio. Moreover, according to the modified sub-band coding (MSBC) voice codec technology began Bluetooth wireless headsets that support HD voice, free calls combined with high quality voice.

HD voice services can be reflected in the existing network. Similar to the narrow-band networks and devices transition to high definition voice, as the extension of the bandwidth (BWE) technology, natural language processing to the terminal of calls are high-quality analog can be used to do not support high definition hp pavilion dv4 battery voice features of the device a compromise solution.

On near High Definition Audio

The bandwidth of conventional telephone system over 300 Hz to 3.4 kHz audio-frequency range is limited, this area is often referred to as narrow-band voice. Although the phone system is digital, but it's the same with the bandwidth of conventional analog system is going. From the point of DELL Latitude E6410 Battery view of voice quality, lack of natural narrow-band speech voice fidelity, often described as thin and blurred. However, the frequency range of narrow band for the full explanation for the degree of votes to identify the approximately 99%.

HD Voice when the sampling Sony VGP-BPL13 Battery frequency of 16 kHz audio bandwidth from 50 Hz to about 7, the speech signal from narrowband voice clear. Although broadband and voice is not significantly improve the understanding of speech, but the limited scope of 3.4kHz to 7 kHz increased friction sounds in words (eg, F, S, E) the degree of identification. Broadband can be a real voice in the natural voice speech subjective audio quality has improved significantly narrow. HD Voice Expansion outside of 50Hz to 300Hz to reduce Toshiba PA3399U-1BAS battery low-frequency characteristics of the narrow high-pitched voice and the expansion of high-frequency tones are much improved.

In the test of subjective voice quality of listening, voice opinion score high-speed (MOS) of 4.5 points, while narrowband voice of 3.2 points (1 poor, 5 very good) was. Improve the quality of voice over broadband to reduce the load on fatigue the ear of the listener, especially when the Sony VGP-BPS13 Battery listener in noisy environments. Network provider Orange mobile phone offers on its website a hearing as an example of the benefits of HD Voice. Orange in June 2010 a new investigation to prove by the end user of the value of other high-definition voice:

* Customer satisfaction of 96% with high definition voice;

* 86% of respondents indicated that they are compatible with HD voice, when the future purchase of a criterion for selecting the telephone;

* 76% of participants were willing to replace the phone for voice HD.

In addition, in 2006, and confirms Ericsson T-Mobile users for the study of the study the benefits of HD Voice. Sample of 150 users in more than 70% of people believe that the best use of mobile voice high definition quality and better after the conversation in a noisy environment, the quality of dialogue.

HD Voice necessary to support the voice communication system for all aspects of the HP Pavilion dv7 battery quality of the voice frequency broadband wide (Figure 2). Technology high definition voice is key in cellular networks by hand and using codec AMR-WB in collaboration. A speech coding wideband AMR-WB, the effective bandwidth of narrowband audio encoding twice as AMR-NB. Finally, a voice of high-definition, cooperation between the base station and handset with AMR-WB encoded transmission of voice, in the process of change or transformation from one end of a speech coding. HD voice connection can not be achieved if the system is in place of the narrow-band-AMR-NB code.

Advanced voiceband

It can be expected, the introduction of high definition voice in the process does not support certain aspects of communication systems, because the conversion to a narrow band voice frequency, the increase even in the lower voice quality, the charge of the hearing. Extension Artificial bandwidth (BWE) in the communication system through the terminal portion of the speech signal to narrow band by the addition of artificially generated sounds to losses in the transmission of high frequency and low frequency voice (Figure 3). BWE to expand in this way, the benefits of high definition audio, and transition to the Sony VGP-BPS13B/Q Battery bandwidth of a mixture of voice communication systems.

BWE algorithm is the use of voice, to appreciate the sound source-filter model and produce a wide frequency range of content of speech. According to this model is the voice of a sound source (eg vocal cords) produces along a simulated channel model. BWE algorithm to estimate the narrowband voice model based broadband noise source, and then use the model to estimate the parameters of the broadband spectrum of their loss. In practice, BWE, regardless of the source coding and Dell Studio 1537 Battery processing route of transmission, so it can be mixed with the narrow bandwidth of conventional telephone networks and coexistence.

BWE is mainly used in Bluetooth headsets and car kits. In these devices, the receiving terminal, the CVSD coded voice signal narrow band is first decoded and then after treatment BWE, then the parties have extended bandwidth speech signals. BWE also in high definition telephone network, which will be enhanced bandwidth of the speech HP 620 Battery signal of 14 kHz ultra-wideband frequency range (SWB) used.

HD Voice and audio accessories

High-definition audio enhancement and voice processing methods (such as noise suppression (NS), echo cancellation (AEC)), and can improve speech understanding in noisy environments, and all can improve. Noise suppression techniques to analyze the noise of a mixture of dialogue and turn off the sound louder voice tag. A lot of noise reduction algorithm for estimating the spectral power Sony VGP-BPS9/b Battery density of noise, noise, and then extracted the dialogue. Compared with treatment narrowband to broadband noise reduction, the calculation of the noise spectrum to increase the frequency of more data on the frequency range of compression noise. In addition to noise suppression, echo cancellation creates the approach eliminates the coupling between loudspeaker and microphone to the sound of the echo signal. Echo cancellation works of the signal received by the microphone to isolate a copy of the filtered and delayed. The echo cancellation Sony VAIO VGN-FZ Battery technology for the calculation of votes in broadband adaptive filter coefficients.

Bluetooth technology in the HD Voice

As the current Bluetooth mobile phone car kits have become popular configuration so important that it is compatible with HD voice. This feature has been the voice codec Bluetooth MSBC reality.

Bluetooth Advanced Audio Distribution Model (A2DP) require the use of sub-band coding (SBC) for the mandatory audio codec, dell studio xps 13 battery handset and headset to ensure interoperability. SBC is a low complexity codec is the compression ratio of moderate support for 16kHz, 32kHz, the sampling rate 44.1 kHz and 48 kHz, and a voice of high-definition, of course, the choice of Bluetooth . In terms of voice, broadband-16kHz, SBC can be compressed 64kbps data rate of 04.01. However, to do if part of the SBC-coding via Bluetooth, it can not be linked to meet the underlying Bluetooth packets. MSBC is a codec technology developed to comply with SBC and Bluetooth data packets in May 2011 and is defined as a Bluetooth Hands-Free Profile 1.6 required in the codec.

In the encoding and decoding performance, with ITU-T G.722 codec comparable MSBC Speaking broadband system is widely used as a decoding Toshiba PA3465U-1BRS battery system, new information on quality. In general, the error MSBC audio signal to the score of voice quality over G.722 plan. MSBC will get multiple encoding encoding / decoding channel to a better average quality than G.722 voice.

Summary

Compared to traditional voice narrow band high definition audio provides excellent voice quality in noisy environments to reduce the burden of hearing. Listening tests and user trials, high-definition voice are shown a significant advantage. Take the mobile network and handset AMR-WB speech codec system, the system of MSBC Bluetooth headset voice codec HD-Telephony use. In addition, the use of mobile phones and headsets, noise reduction and echo cancellation algorithms, high-definition audio experience for the best voice quality. As network operators and Dell Latitude D630 Battery equipment manufacturers will gradually introduce the consumer market, the HD-phone, Bluetooth headset on the approach of expanding the bandwidth to bring the benefits voice users and high-definition mixed tape bandwidth mobile network.

 

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