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g711编码原理

G.711编码原理

G.711编码是一种常用的音频编码标准，用于将模拟语音信号转换为数字信号，以提高通信效率和节省带宽。本文将介绍G.711编码的基本原理.

G.711编码使用了基于时域的脉冲编码调制（PCM）技术，将模拟语音信号进行采样和量化，然后将其转换为数字信号以进行传输. G.711编码标准主要包括两种压缩算法：μ律编码（μ-law）和A律编码（A-law）.

μ律编码是在北美和日本广泛使用的一种算法，而A律编码则是在欧洲和国际上使用的一种算法. 这两种编码算法在原理上相似，都是将模拟信号映射到更小的动态范围内以减小信号的位数.

在μ律编码中，信号的动态范围被分为255个离散级别. 较大幅度的信号将被映射为较小的幅度，而较小幅度的信号将被映射为较大的幅度. 这种非线性映射允许更高的精度分配给较小幅度的信号.

在A律编码中，信号的动态范围被分为一个更精细的离散级别，共有87个级别. 类似于μ律编码，A律编码也将较大幅度的信号映射为较小的幅度，反之亦然.

G.711编码使用8位字节表示每个采样样本，通过这种方式将带宽减小到64

kbps. 这使得G.711编码在语音传输和存储中具有广泛的应用.

总结一下，G.711编码是一种常用的音频编码标准，它通过采样、量化和非线性映射的过程，将模拟语音信号转换为数字信号以实现高效传输. 在实际的应用中，人们可以根据地区使用的标准选择μ律编码或A律编码算法来进行编码过程。

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1Data sheetNokia ONT G-2425G-A (external antenna)The Nokia ONT G-2425G-A is a dual-band Wi-Fi 5 mesh system with Wi-Fi Alliance compliant Wi-Fi EasyMesh, enhanced by Nokia value added features.The Nokia WiFi Mesh Middleware creates a self-healing, self-optimizing network and includes intelligent channel selection, band steering, client steering and backhaul management to provide the best Wi-Fi performance. As it is EasyMesh™ compliant, it provides interoperability and avoids vendor lock-in.Optionally, the Nokia ONT G-2425G-A can be managed by the Nokia WiFi Cloud Controller. The associated Home Console presents the help desk agents with a real-time holistic view of the in-home network to assist them with easy identification and instantaneous resolution of issues. The Network Console provides an end-to-end Wi-Fi network view and allows management of groups of Wi-Fi networks.Nokia ONT G-2425G-A (external antenna)Residential gateway – ONT for the intelligent mesh networkThe Nokia ONT G-2425G-A is the solution for home networking that is delivered by Gigabit Passive Optical Network (GPON). The device has built-in concurrent dual-band Wi-Fi® 802.11b/g/n and 802.11ac networking with triple play capabilities that include voice, video and data using high-capacity Wi-Fi connectivity. The G-2425G-A supports Wi-Fi 5 and Wi-Fi EasyMesh™, to create a whole home mesh network. This coverage can be expanded at any time by installing additional Wi-Fi EasyMesh-capable beacons to ensure seamless roaming throughout the home. The G-2425G-A includes the Nokia WiFi Mesh Middleware which ensures the best possible Wi-Fi performance. The end-user experience is enhanced by the service provider’s Wi-Fi management capabilities in the cloud and intuitive home user support using the Nokia WiFi mobile app.2Data sheetNokia ONT G-2425G-A (external antenna)This Nokia indoor ONT is designed to deliver triple play services (voice, video and data) to residential subscribers. Voice services are provided through two plain old telephone service (POTS) ports with an integrated analog telephone adapter (ATA) that converts voice traffic into Session Initiation Protocol (SIP). Connectivity to an existing public switched telephone network (PSTN) Class 5 switch is supported through SIP with direct interoperability of a variety of soft switches. Ethernet connectivity is available on four Gigabit Ethernet (GigE) ports, all of which have the ability to burst up to a full gigabit dynamically. Service providers can deliver video using IP packets (IPTV).Relying on dual-band Wi-Fi allows for support of the widest range of customer products. The IEEE 802.11ac standard enables gigabit speeds on many newer devices, while the widely supported 802.11b/g/n standard can simultaneously connect to legacy devices.Features• Four RJ-45 10/100/1000 Ethernet ports• Two POTS ports for carrier-grade voice services• Dual-band concurrent Wi-Fi: 2.4GHz and 5GHz• Wireless IEEE 802.11b/g/n: 2.4GHz• Wireless IEEE 802.11ac: 5GHz• Network Address Translation (NAT) and firewall• Voice interworking function from the analog POTS lines to the voice over IP (VoIP) and Ethernet layers• Two USB 2.0 host ports• Optics support received signal strength indication (RSSI)• Supports virtual private network (VPN) passthrough for Point-to-Point Tunneling Protocol (PPTP), Layer 2 Tunneling Protocol (L2TP) and IPSec• Port forwarding and demilitarized zone (DMZ)/ dynamic domain name system (DDNS)Benefits• EasyMesh enhanced by Nokia value added features • Integrates the ONT and wireless access point functions to allow for one less device in the home• Delivers connectivity to Ethernet devices within the home• Supports full triple play services, including voice, video and data• Allows service-per-port configurations• Supports IP video distribution• Supports easy-to-use USB 2.0 connections for external disk drives and home network attached storage (NAS)• Delivers voice services using VoIP• Delivers video services efficiently with multicasting or unicasting• Facilitates network management using Nokia 5520 AMS• Flexible video delivery options of Ethernet or wireless to set-top boxes (STBs)Technical specificationsPhysical• Height: 131 mm (5.1 in) –Excluding antenna of 170 mm (6.7 in)• Width: 170 mm (6.7 in)• Depth: 30 mm (1.2 in)• Weight: 0.42 kg (0.92 lb)Installation• Desk mountable• Wall mountable with bracketOperating environment• Temperature: -5°C to 45°C (23°F to 113°F)•

凌志R780G板载显存的设置方法

1， 进入BIOS设置界面 ,点击图中加亮部分的Chipset Configuration(如图1)

图1

2，进入Chipset Configuration选项卡，选择NorthBridge Configuration设置，图中加亮部分

（如图2）

图2

3，进入下图界面后点击Internal Graphics Configuration，如图3加亮部分。

图3

4，进入下图页面后使用键盘“↑”“↓”键可针对板载显存进行设置。如图4

图4

5，点击Internal Graphics Mode弹出下图界面。选择Disable模式，可关闭主板集成显卡输

出，此模式需使用外置显卡输出；选择UMA模式，仅使用主板集成显卡芯片输出，此时板

载显存不起作用，显示芯片从内存调用共用显存；选择SIDEPORT模式，仅使用板载显存

工作，此时显示芯片不从内存调用共享显存；选择UMA+SIDPORT模式，既支持板载显存，

同时又支持显示芯片从内存调用共享显存。如图5

图5

6，点击UMA Frame Buffer Size，可以设置显示芯片从内存调用的共享显存大小，如图6

图6