Tamil Blog Electronics

Contact Me for Project Prize Mail Id:  tamilblogelectronic@gmail.com Measure Traffic density and ambulance detection in Realtime project. What We Do in This Project: (Both Software & Hardware Project Available) ( i) Traffic Density Measure - Realtime (Means using Traffic Camera or Traffic Video) First,  we do Vehicle Detection in Video/Camera using Image Processing. Second, we Count the Vehicle We Detected in Video/Camera using Image Processing. Third, We Compare Two lane Vehicle Density in Video/Camera , if lane detect more no. of vehicle will be Prioritized first.   (ii) Ambulance Detection in Single Lane  - Realtime (Means using Traffic Camera or Traffic Video) : First, We Collect the Images of Ambulance. Second, we train our Image model using sample ambulance image. using Yolo image Model, we able to Detect the Ambulance in Video/ Camera. (iii) Ambulance Detection in Multiple Lane  - Realtime (Means using Traffic Camera or Traffic Vid...

  Definition of Robot By Robot Institute of America: Any machine made by one our members. A robot is a software-controllable mechanical device that uses sensors to guide one or more end-effectors through programmed motions in a workspace in order to manipulate physical objects. Classification of Robot I JIRA ( Japanese Industrial Robot Association) Robots can be classified as follows:  Class 1:  manual handling device – a device with several DOF’s actuated by the operator.  Class 2:  fixed sequence robot – similar to fixed automation.  Class 3:  variable sequence robot – similar to programmable automation.  Class 4:   playback robot – the human performs tasks manually to teach the robot what trajectories to follow.  Class 5:  numerical control robot – the operator provides the robot with the sequence of tasks to follow rather than teach it.  Class 6:  intelligent robot – a robot with the means to understand its en...

  What is a heat sink ?    The maximum power dissipated by a   power transistor and transistor junction temperature are closely related because junction temperature increases due to power dissipation.  Hence it is necessary to keep the junction temperature below the maximum specified value or else the crystalline semiconductor structure will get permanently damaged.  The power transistor is mechanically attached to a metal surface that provides a large surface area for heat dissipation to the surrounding air.    The mechanical device is called a heat sink. The heat sink takes away the heat from the power transistor via thermal conduction and expels the heat to the surrounding air by thermal convection and radiation. Advantage of heat sinks are: Temperature of the transistor casing gets lowered The power handling capacity of the transistor can now approach the rated maximum value.   

  The crystal behaves like an inductor by operating at a frequency slightly above   fs (series resonant frequency) . This is basically a Colpitt’s oscillator where the input stray capacitance C1 and output stray capacitance C2 and the   crystal as inductor L form the Colpitt tank circuit. The frequency of oscillation is stabilized by using a crystal operating at either its series or parallel resonant frequency. R1 nd R2 with Re form the divider bias circuit. The RFC or radio frequency choke (inductor) isolate the power supply (dc voltage)   from the ac signal generated.

Factors that affect frequency stability of an oscillator are: Due to changes in temperature, the values of the components of the tank circuit i.e. inductors and capacitors get affected. This causes change in frequency of the oscillator. Due to changes in temperature, the h parameters of the transistor gets changed which in turn affects the frequency. Changes in environmental conditions like temperature, humidity etc. affects the frequency of operation. Stray capacitances, changes in load connected to the oscillator also changes the frequency. Variation in power supply can affect frequency stability. Ageing of the crystal or tank elements changes the internal dimensions and hence frequency changes will be seen.   Frequency stability can be improved by the following modifications: Enclosing the circuit within a constant temperature   enclosure Connecting the oscillator to an emitter follower so that load variations do not affect the frequency stability. Have a well regulated...

Frequency : At what frequency should the oscillator work. e.g. 40 MHz Type of signal generated : Sine wave or square wave. If square wave TTL or CMOS etc. Stability : The most important specification is stability. Stability is how well an oscillator remains at the desired frequency. The measurement of stability is the deviation or change  in frequency from the desired value. The stability is typically measured in parts-per-million (ppm) . High performance oscillator’s stability will be specified in scientific notation e.g. 1x10 -6 is 1ppm. Temperature range of operation : Oscillators are measured according to their intended use, which means the temperature range may be 0 to 50 ºC for indoor applications, –40 to +70 ºC for outdoor applications, or some other range. Power supply voltage :  e.g. 5V±5%  or 15 V ±10% Current drawn :   e.g.  30 mA Package of the oscillator : type of package Dimensions : Height, length and width in mm. Spacing between cry...

What is Pulse Amplitude Modulation ?  ● An analog pulse modulating scheme in which the amplitude of the pulse carrier varies proportional to the instantaneous amplitude of the message signal.  ● The pulse amplitude modulated signal, will follow the amplitude of the original signal, as the signal traces out the path of the whole wave.  ● In natural PAM, a signal sampled at the Nyquist rate is reconstructed, by passing it through an efficient Low Pass Frequency (LPF) with exact cutoff frequency.  ● Pulse amplitude modulation is used in the popular Ethernet communication standard.  ● There are two categories of PAM techniques, one is the pulses have the same polarity and the other in which the pulses can have both positive and negative polarities according to the amplitude of the modulating signal. ● By varying the width of the pulses (the carrier signal) in proportion to the instantaneous values of the analog signal (the message signal)  ● The...

  What is Noise?  • Noise is the disturbance we hear.  • It is an unwanted signal that corrupts the desired message signal.  • Electrical Noise is an unwanted signal that appears along with the Desired Electrical Signal and falls within the same frequency band as that of message signal.  • Noise signals are random signals. They are non-deterministic in nature.  • The desired deterministic signals can be modeled mathematic Categories of Noise  • Correlated – this noise the one which is present whenever message signal is present.  • Uncorrelated – this noise is the one which is present even if the signal is not present. (Correlation means a relationship between message signal and noise) Classification of Noise 1. External Noise  a. Atmospheric Noise (above 30 MHz)  b. Extraterrestrial noise (large spectrum covering all communication frequencies)       i. Solar noise       ii. Cosmic Noise  c....

What is Amplitude Modulation?   Amplitude of the carrier is changed in accordance with the modulating signal amplitude, but the frequency remains constant.  Hence the carrier wave envelope follows the message signal amplitude.  The maximum and minimum amplitude in AM signal can be varied to have change in modulation depth. Advantages  ● AM is usable with simple modulators and demodulators  ● Relatively inexpensive  ● AM wave can travel longer distance comparatively  ● Large coverage area than other modulations  Disadvantages  ● Poor performance in the presence of noise  ● Transmitted power is wasted in sidebands  ● Wastage of bandwidths  Applications  ● Used in low quality modulation employed for commercial purposes for broadcasting audio and video signals.  ● Used in two-way mobile radio communications such as citizens band(CB)  ● Aircraft communication in VHF band.

The Elements of Basic Communication system • Information or message input signal  • Input Transducer  • Transmitter  • Communication channel or medium  • Noise (unwanted signal getting added along the way)  • Receiver  • Output Transducer  • Recovery of original information or message signal. 1. Information or input signal  It may be a speech or music, picture, video, data   2. Input Transducer  Message signals cannot the transmitted as it is. First it has to be converted into a suitable electrical signal. The input transducers commonly used in the communication systems are microphone, camera.  3. Transmitter  This block converts the electrical signal to a suitable modulated signal. The power of the modulated signal should be increased in order to cover a large range. This can be done using electronics circuits such as amplifier, mixer, oscillator, and power amplifier.  4. Communication channel or medium Channel...

 What is FIR Filters? The filters designed by using finite number of samples of impulse response are called FIR filters. These finite number of samples are obtained from the infinite duration desired impulse response h (n). Here h (n) is the inverse fourier transform of H (O), where H (0) is the ideal (desired) frequency response. The various methods of designing FIR filters It differs only in the method of determining the samples of h(n) from the samples of h (n). The various steps in designing FIR filter are i) Choose an ideal (desired) frequency response, H.(w). ii) Take inverse fourier transform of H (w) to get h,(n) or sample H, (o) at finitenumber of points (N-point) to get Ĥ(k). iii) If h (n) is determined, then convert the infinite duration h (n) to a finite duration h(n). (usually h(n) is an N-point sequence) or If ħ(k)is determined then take Npoint inverse DFT to get h(n). iv) Take Z-transform of h(n) to get H(z), where H(z) is the transfer function of the digital filter...

 The monolithic IC is one in which all circuit components are fabricated into or top of a block of silicon which is referred to as chip (or die). Interconnections between the components within the chip are made by means of metallization patterns, and the individual components are not separable from the circuit.  The processing steps used to fabricate various silicon devices, such as diodes, transistors, and integrated circuits are as follows:  1. Refining and growth of Silicon Crystals  2. Si Wafer preparation  3.Oxidation  4. Photolithography  5. Diffusion (and ion implantation) of dopant impurities  6. Chemical vapour deposition (including epitaxy)  7. Metallization.  8. Testing and chip separation  9. Packaging The fabrication of devices starts with single-crystal silicon wafers.  Then the processes listed above can be used to produce discrete devices (i.e., individual diodes and transistors) and ICs.  These devices or ...

 Ion implantation is an alternative to deposition diffusion and is used to produce a shallow surface region of dopant atoms deposited into a silicon wafer.  In this process a beam of impurity ions is accelerated to kinetic energies in the range of several tens of kV and is directed to the surface of the silicon.  As the impurity atoms enter the crystal, they give up their energy to the lattice in collisions and finally come to rest at some average penetration depth, called the projected range expressed in μm.  Depending on the impurity and its implantation energy, the range in a given semiconductor may vary from a few hundred angstroms to about 1 μm.  Typical distribution of impurity about the projected range is approximately Gaussian. By performing several implantations at different energies, it is possible to synthesize a desired impurity distribution, uniformly doped region. A gas containing the desired impurity is ionized within the ion source. The ions are ...

At this step, the microarchitecture of the design is implemented using hardware description languages such as VHDL, Verilog and System Verilog.   Logic Synthesis: Use an HDL (VHDL or Verilog) and a logic synthesis tool to produce a net list a description of the logic cells and their connections.  System Partitioning:  At this step, we divide the largely sized die into ASIC sized pieces.  Pre-Layout Simulation:  At this step, a simulation test is done to check whether the design contains any errors. Floor Planning:  At this step blocks of netlist are arranged on the chip.  Placement:  At this step location of cells inside the block is decided. Routing: At this step, connections are drawn between blocks and cells.  Extraction:  At this step, we determine the electrical properties like resistance value and the capacitance value of interconnect. Post-Layout Simulation:  Before the submission of the model for manufacturing this si...

  ASIC [“a-sick”] is an acronym for Application Specific Integrated Circuit.   ASIC is a tailored made ICs for a particular application.  Generally an ASIC design will be undertaken for a product that will have a large production run, and the ASIC may contain a very large part of the electronics needed on a single integrated circuit.  These are usually designed from root level based on the requirement of the particular application. Some of the basic application-specific integrated circuit examples are a chip for a toy bear that talks; a chip for a satellite; a chip designed to handle the interface between memory and a microprocessor for a workstation CPU.  These chips can be used only for that one application for which these are designed.   The main advantage of ASIC is reduced chip size as a large number of functional units of a circuit are constructed over a single chip. Types of ASIC: 1.Full Custom 2. Semi- Custom Standard Cell Based G...

 The twin-well employs two separate wells CMOS structure which are implanted into very lightly doped silicon.  This allows the doping profiles in each well to be tailored independently so that neither type of device will suffer from excessive doping effects.  The lightly doped silicon is usually an epitaxial layer grown on a heavily doped silicon substrate. The substrate can be either n-type or p-type.  The Process steps for a twin-well CMOS structure i) The starting material is lightly doped epitaxial layer over a heavily doped n+ <100> orientation substate.  ii) A composite layer of SiO2 and Si3N4 is defined and silicon is exposed over the n-well region. Phosphorus is implanted as the n-well dopant at low energy and enters the exposed silicon, but is masked from the adjacent region by Si3N4.  iii) The wafers are then selectively oxidized over the n-well regions. The nitride is stripped and boron is implanted for the p-well. The boron enters the...

 The silicon-on-sapphire (SOS) CMOS structure is a heteroepitaxial CMOS structure in which a thin (~1 μm) single crystal silicon epitaxial layer is deposited on a highly polished single-crystal sapphire substrate.  The silicon film is doped n+ and p+ by phosphorus and boron ion implantation, followed by an annealing or drive-in diffusion step, as required. The thin silicon film is then etched into many separate NMOS and PMOS devices and interconnected by the metallization pattern.  The (SOS) CMOS structure is an example of a dielectrically isolated IC, and the use of the insulating substrate results in a greatly reduced parasitic capacitance. This leads to a very high-speed device performance and very low power dissipation.  These features are especially useful for very high-speed, high-density ICs.  The Steps in the SOS CMOS process   i) The starting wafer is sapphire (aluminium oxide, Al203) on which silicon, whose crystal lattice is compatible with ...

 Advantages of CMOS : 1. Minimum feature size  2. Low static power consumption  3. Gate propagation delay in the order of nanoseconds  4. Consumes very low power, particularly, at low frequency.  5. The large logic voltage swing, with the high-state output voltage being very close to +VDD  6. The low-state output voltage dropping is very close to either ground potential or the negative supply voltage.  7. CMOS provides lower delay and lower dc power dissipation  Applications:  1. Prime choice for high speed, high density applications.  2. And also in applications requiring minimum power.  Disadvantages:  1. CMOS requires greater process complexity and increased chip area (about 10 to 30 % compared to NMOS).  2. CMOS design is to have both p-channel and n- channel transistors on the same wafer. This leads to two different approaches to CMOS: the traditional p-well approach with proven reliability and the newer n-well approa...