CHAPTER-1
INTRODUCTION
1.1 Introduction to ADC:
Analog refers to physical quantities that vary continuously instead of discretely. The physical phenomena typically involve analog signals. We have many examples like speed, temperature, pressure, voltage, etc. But microprocessors work with digital quantities, means the values which are taken from discrete domain. To interact analog systems with digital systems or digital systems with analog systems conversion is needed. There are 2 types of conversions: (1) Analog to digital converters (ADCs), (2) Digital to analog converters (DACs).
FIGURE1.Analog to Digital converter
In the analog to digital converter the input vary from minimum to maximum value of volts or amperes. The output is a digital number that represents the input value. In the digital to analog converter the input that specifies an output whose value changes in steps. These step changes are in volts or amperes. Analog to digital conversion techniques have become extremely important. In this a great deal of technical effort has gone to produce analog to digital converters. Which are accurate, fast, and cheap.
FIGURE2. Digital to Analog converter
The ADC and DAC are together used in digital systems to provide complete interface for control systems with analog sensors and output devices. These type of systems are used in automotive engine controls. In this type of systems it is much easy to convert analog to digital signal and digital to analog signal.
FIGURE3. Digital control system with analog I/O
In the modern electronic systems, signal processing and storage are performed in the digital domain. For these type of systems conversions between analog and digital signals are required. In the adva...
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...ich are considered in analog to digital converter are current source, comparator and error sources.
In a non ideal current source, the output impedance may be finite. In this case the value of current will be dependent on output voltage. Because of this we will introduce non-linearity to the entire ADC. This will reduce the non-linearity below the accepted level and imposed by the ADC resolution. In this situation the output impedance must be very high.
Comparator is the most important part of the ADC. Why because the resolution of the comparator must be smaller than the ADC resolution, and also a reasonable speed is needed to get the minimum delay in the comparator. The delay of the comparator influences on the counter measured time. In the comparator design, there is one fact that the input common mode voltage varies for different levels of the input sample.
As we can see in the above example, the iValue1 and 1.0 are the two operands and which are not of the same type. One is the integer and the other is a double precision floating point value. Therefore, the above expression is an example of mixed mode expression.
8. Computers are said to process data digitally because the data is processed in binary bits.
The input signal is divided into three subbands which are then transformed into the frequency domain using a variable block length. Transform coefficients are grouped into nonuniform bands to reflect the human auditory system, and then quantized on the basis of dynamic sensitivity and masking characteristics. ATRAC compresses compact disc audio to approximately 1/5 of the original data rate with virtually no loss in sound quality. 1 Introduction --------------
Digital is free from errors while analog has a few mistakes sometimes. Digital items know the exact answer so they do not really have mistakes, but analog may make you do the whole thing on your own because someone wouldn’t
There are a great number of applications for Digital Signal Processing and in order to better understand why DSP has such a large impact on multiple aspects of society, it helps to better understand the wide variety of applications it can be used for. Here we will briefly look into the following applications of Digital Signal Processing and their uses; speech and audio compression, communications, biomedical signal processing and applications in the automobile manufacturing industry. Li Tan [1] goes into detail with each of these applications in his book, Digital Signal Processing, and explains how each are used on a daily basis.
For the prevantion of the electricity blackout we need to build smart power grid. A modernized electrical grid that uses analog or digital information and communications technology to gather and act on information, such as information about the behaviours of suppliers and consumers is known as a smart grid. This is used to improve the efficiency, reliability, economics, and sustainability of the production and distribution of electricity in an automated fashion[12]. The important aspects of smart grid is to electronic power conditioning and control of the production and distribution of
According to previous research works, while the analog circuits including amplifiers and bias circuit take about half of the overall
Basic Mathematics for Electronics seventh edition: Nelson M. Cooke, Herbert F.R Adams, Peter B. Dell, T. Adair Moore; Copyright 1960
In this paper, I will talk about how AC circuits can be described by considering voltage and current using complex numbers. An AC circuit requires two separate numbers to be able to completely describe it. This is because it takes into account the amplitude and the phase of the current. The fact that complex numbers can be easily added, subtracted, multiplied or divided with each other makes them ideal for this operation where both amplitude and phase have to work together.
Digital signals convert regular signals into strings of ones and zeros, which is much more efficient than analog signals. Broadcasters can maximize their use of channel space because digital signals carry significantly more information than analog signals. Several digital programs and services can be sent in the space occupied by a single analog channel. The result of this is that the consumer is provided with more channel choices(FCC).
P Cruise et al., “A Digital-to-RF-Amplitude Converter for GSM/GPRS/EDGE in 90-nm Digital CMOS,” IEEE Radio Frequency Integrated Circuits (RFIC) Symp., pp. 21–24, June. 2005.
All useful generators of electricity come in two basic forms, alternating current and direct current. Direct current (dc) comes from generators that do not change in polarity, always producing a positive charge. In alternating current (ac) the polarity of the terminals is always changing from positive to negative. Thus you are left with alternating current flow. There are different ways of measuring and generating alternating and direct current.
Optical computing means performing computations, operations, Storage and transmission of data using light, instead of silicon chips. Optical computers are not completely discover. Optical, computing generally means that the optical manipulation of discrete manipulating data. The hope for optics lies in doing things that are provably impossible for electronics. This paper is consist of different types of optical computing (mainly digital analog and quantum), how the networks has been transported in optics (since 1990, SDH, and SONET specifications have been extended based upon the demand for the transport of new tributary signals and also based on new capabilities provided by the evolution in component technology), architecture of optical computing. Optical computing is safe for human use because of free from electrical short. The basic requirements of an optical computing architecture for information processing are: (i) optical sources (ii) input information for processing (iii) a method of modulating the sources to carry the input information and finally (iv) an information processing or decission making
The information can be expressed through words, numbers, sounds, and images. By better understanding digital technology, we improve our control over such information.
Digital Era is also known as ‘Information Age’, or ‘New Media Age’. Digital Era helps to create knowledge based society surrounded by high technology which helps individuals to explore their personal needs. In the