catv modulator

CATV is the abbreviation of "Community antenna television", that is, sharing antenna TV. CATV Network is the "CATV network", is an efficient and inexpensive comprehensive network, it has a wide bandwidth, large capacity, multi-function, low cost, anti-interference ability, support a variety of services to connect the advantages of thousands of households, its de

CATV Network is an efficient and inexpensive comprehensive network, it has a wide bandwidth, large capacity, multi-function, low cost, anti-interference ability, support a variety of services to connect the advantages of millions of households, its development for the development of Information superhighway laid a foundation. In recent years in China CATV Network development, the country has built more than

backplane capacity exceeding 1Gbps. CMTS allows cable operators to establish high-density and highly adjustable termination systems for their data-over-cable (DoC) services. The core module of CMTS is cable Access Router, which provides routing connections from the Internet or from the internal backbone data network to the RF (CATV) network. By working in conjunction with the QAM modulator (downlink module

and demodulation techniques are described below.Quadrature amplitude Modulation (QAM)In modern communication, it has been one of the focus of attention to improve the spectrum utilization. Quadrature amplitude modulated QAM (quadrature amplitude modulation) is a kind of modulation method with high frequency spectrum utilization, which has been widely used in medium and large capacity digital microwave communication system, CATV network high-speed dat

range. Noise shaping can therefore be used to push noise into a higher frequency spectrum. What is useful is that more space is created to dump the noise. And because the spectrum is above the audible range, the noise is inaudible.The higher-speed sampling frequency can be achieved in the following two ways: Use a higher sampling frequency at the beginning. This method is used on the PDM microphone, and the typical sample rate is 3MHz. A known signal is interpolated, and the signal

-olt) which is placed in the cell room, ONACCESS5XXX series low cost optical switch and the optical Network unit placed on the user side (Optical network unit- ONU) OnAccessH1001 composition. Transmission medium is single-mode fiber, can choose single fiber, also can choose double fiber. A onaccess5xxx optical switch can connect up to 24 users of the ONACCESSH1001 Optical Network unit, ONACCESSH1001 can also line up to 4 computers or IP telephony. If the user has only one computer can choose OnA

the Optical Network Unit-ONU) onaccessh1001. The transmission media is a single-mode optical fiber. You can select either a single fiber or a dual fiber. An OnAccess5xxx optical switch can connect to the OnAccessH1001 optical network unit of 24 users. OnAccessH1001 can be connected to up to four computers or IP phones at the same time. If you only have one computer, you can select the OnAccess1001 Optical Fiber Nic to be inserted into the computer and directly connect to the optical fiber. The

communication and CATV access cable Resources in the residential area belong to all operators. Another feature of China's FTTH target market is the existence of industry barriers in the telecom business: telecom operators are not allowed to operate CATV services, and this situation cannot be changed for quite some time in the future. 2. Selection of FTTH Optical Fiber Access Technology in China1) Passive O

commercial buildings, are generally equipped with communication equipment rooms for installing communication access equipment and line handover for the entire residential area, this configuration is required for telecom operators to compete with each other and comprehensive access to a variety of telecommunication services. The distance between data centers and users is generally less than 1 km; major telecom operators and cable TV operators have already laid 4 to 12 cores in general.) optical

the residents of residential areas in large and small cities. Urban residential areas are generally garden-type residential areas, which are characterized by high household density, A single Garden Residential Area generally has-households, and some even tens of thousands of households. residential areas, including commercial buildings, are generally equipped with communication equipment rooms for installing communication access equipment and line handover for the entire residential area, this

have 18-bit resolution AD1879. With the improvement of design and process level, a high speed sigma-Delta analog-to-digital converter has been developed. such as AD7723 (1.2MSPS), AD9260 (2.5MSPS) and so on.The theoretical basis of the 2.∑– type ADCUnlike the General ADC, the∑– ADC is not quantified directly based on the size of each sample value of the sampled data, but rather on the size of the difference between the previous measure and the latter value, the so-called increment .Quantitative

[Abstract]: Modern communications to digital, broadband, intelligent, integrated development, the rapid development of digital technology has been CATV network, telephone network and data network closely linked to provide a variety of different types of information services, video on demand is one of them. This paper introduces the digital set-top box in VOD system, including the key technology, relevant standard and concrete realization method of STB

As The first company in China that specializes in R D and production of Fiber To The Home-FTTH equipment, we have recently received many FTTH application requirements To communicate with different types of FTTH users, we found that many users have misunderstandings about FTTH technology selection and application. These misunderstandings include ignoring the FTTH technical risks and blindly requiring full-service access; failing to understand the FTTH market characteristics in China, and blindly

system. So now there are a lot of big and small new old companies, have invested a greater power to develop WDM technology and new optical devices. 1 Key devices To construct the future high-speed and high-capacity information network system with optical network, we need to focus on high speed optical transmission, multiplexing and multiplexing technology. Based on optical interpolation multiplexing (OADM) technology, Optical Cross Interconnection (OXC) technology, integrated narrowband, high

effective method for measuring the MPEG-Ⅱ bit rate at the decoder or system layer multiplexing receiver. Use an MPEG decoder chip and an embedded processor to centrally manage the reference clock of the MPEG-Ⅱ Transfer Stream program. Because the reference clock of the MPEG-Ⅱ transmission stream program is set based on a certain encoder system's reference clock, the bit rate of the stream can be basically determined through real-time monitoring, at the same time, compare the reference clock of

I. Overview 1. Current status and progress of domestic CATV network Radio and television is the largest media in China, it provides radio and television broadcasting services from wireless to cable, has the largest number of information audiences, is the biggest advertising, economic, market, entertainment and cultural information collection, production, dissemination and provider. By 1999, CCTV and more than 20 provincial-level television stations

. Several optical access methods 2.1 Optical Fiber Distributed Network (FDN)FDN is divided into active and passive optical fiber networks.The difference between a passive optical fiber network and an active optical fiber network is that it replaces a remote Optical Fiber Device (ROLT) in an active optical fiber network with a pair of optical passive splitter ). the transmission protocols used by the two are also different. The active optical fiber network adopts PDH or SDH transmission protocols

name [32]: The name of the output. _ U32 type: The type of the output. The supported output types areV4l2_output_type_modulatorFor an analog TV modulator,V4l2_output_type_analogFor basic analog video output, andV4l2_output_type_analogvgaoverlayFor analog VGA overlay devices. _ U32 audioset: The set of audio outputs which can operate with this video output. _ U32 Modulator: The index of the

antialiasing filter is a unipolar, low-pass filter, shown in 2, which uses a series resistor (R) and a common mode capacitor (CCM). The first step in designing this filter is to select the desired cutoff frequency, FC. On the FC, the response of the filter is rolled down to -3db, and the frequency range continues to be reduced by the speed of the -20db/10 times octave.Select a cutoff frequency that is at least 10 times times lower than the ADC modulator