Digital Television Technology
Digital Television Technology:
The wonders of digital television have been heralded for more than two decades. Compared to old analogue technology, the digital compression allows more channels to be transmitted with better image quality and improved interactive applications. Roughly 6 times as many channels can be the broadcast with same amount of transmission capacity as is currently used for one analogue channel. The switch off of the analogue signal could result in a large increase in the supply of television channels available to viewers or in bandwidth being freed up for other uses.This paper aims at providing a framework for discussing the policies for the transition from analogue to digital television .
HARDWARE ARCHITECTURE
This section details architectures that implement the embedder
and detector .
A. Watermark Embedder:
We assume in our implementation that the input video to the embedder is provided as a stream of pixel data. That is, the elements are provided one row at a time, beginning with the first row and ending with the last. The data rate is assumed to be consistent with the frame rate of real-time video There is a unidirectional flow of data from the input to the output. Each block simply processes a few elements of data (pixels) and forward the results to the next block—there are no iterative operations.
Watermark Detector
As with the embedder, the detector is architected to function as a stage in a system-level pipeline designed to process real-time video data, with the same input data stream characteristics. However, in contrast to the embedder, the detection algorithm is considerably more complex.Detection consists of a series of computations that operate on an entire matrix, as opposed to elements of a data stream. Moreover, the computations themselves are iterative. Both of these aspects will result in prolonged calculations and potential blockage; the
architecture must compensate to prevent the blockage from adversely affecting the real-time performance.
Hardware versus Software :
A watermarking system can be implemented with either software or hardware. In a software implementation, the algorithm’s operations are performed as code running on a microprocessor. For example, high-level scripts written for a symbolic interpreter running on a workstation or machine code software running on an embedded processor are both classified as software implementations.
Question answers:
Q1:What is bit rate reduction?
Ans: Bit Rate Reduction (BRR) also called Bit Rate Reduced, is the name given to Audio compression method used on the SPC700 sound coprocessor used in the SNES as well as the audio processors of the Philips HD1 and Sony play station. BRR compresses each consecutive sequence of sixteen 16-bit PCM samples into a block of nine bytes. From most to least significant, first byte of each block consists of four bits indicating the range of the block (see below), two bits indicating the filter (see below), and two bits of control information for this S P C 700. The remaining eight bytes consist of 16 signed 4-bit nibbles which correspond to the 16 samples, packed in a big in dean manner.
Q2: write down the revenue-generating services of wireless broadcasters?
Ans: wireless broadcasters to offer a variety of powerful revenue-generating services,
including:
• Internet access at blazing speeds;
• multi-user network games;
• video on demand;
• streaming video and audio;
• home banking services;
• e-commerce applications;
• PC software upgrades;
• Broadcasting rich multimedia content; and
• electronic newspapers.
Q3What is Real-Time Performance?
Ans: Real-time performance is maintained by ensuring that the detector does not block the stream of pixels. Due to the shared fold buffer in the architecture, pixels cannot be processed by fold while the fold buffer is being used by the fft, ifft, and pwm operations; this blockage must be compensated for by properly sizing the input FIFO.
Q4:Classify the international standards and solutions developed by DVB over the past few years?
Ans: The international standards and solutions developed by DVB over the past few years can be classified and summarized as follows:
1. DVB-S—An international standard for transmitting digital television
using satellites.
2. DVB-C—An international standard for transmitting digital television
using digital cable systems.
3. DVB-T—An international standard for transmitting digital television in a
terrestrial environment.
4. DVB-MC/S—An international standard for transmitting digital television
using the microwave multipoint video distribution systems.
5. DVB-SI—An international standard that defines the data structures that
accompany a digital television signal.
6. DVB-CA—An international standard that defines digital television security
standards.
7. DVB-CI—An international standard that defines a common interface to
the digital TV security system.
8. DVB-I—An international standard for deploying interactive TV.
9. DVB-Data—An international standard designed to allow operators to the
deliver software downloads and the high speed data services to customers.
10. Interfaces—An international standard that defines digital TV interfaces to
high speed backbone networks.
Q5: Explain what is audio processing unit or AUP?
Ans: The APU is able to accept the audio input signal, interact with user to provide operations on data, and the output a modified audio signal First, the APU samples audio input to it at 48kHz with 20-bit precision. This is accomplished by means of a stereo codec chip included on the Xstend board. This codec performs both digital to analog and analog to digital conversion. When converted to digital medium, signal may then be processed as desired. To determine what operation to perform,APU ha the user-friendly interface to world. For these particular application, LCD display is used to display messages and the push buttons to select the different options. What this allows is the selection of number of different parameters, which translate into the specific operations. Each of these operations is performed by 1 of the three data path components.
The first component of this datapath is FFT module. It is the basic operation is to provide a conversion from the time-domain signal to a frequency-domain signal, and allows processing of the signal in these domain. Frequency shifter follows FFT section to provide the pitch shifting of input voice signal in real-time. The storage component is the final component of datapath. It is the basic purpose is to perform 1 of 2 operations. First, it stores certain amount of input data as determined by either the user or the available memory size. Following this, it plays that stored data back. Effectively this creates the audio record and playback device, which is useful in many of the applications.
GATE Syllabus-
1. Gate Syllabus for Electronics and Communication 2014
2.Gate syllabus for Electrical Engineering 2014
3. Gate syllabus for Engineering Science 2014
IES Syllabus-
1. IES Syllabus for Electronics and Communication
2. IES Syllabus for General Ability
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