- Electronics and Communication, Applied Electronics
• Define Transponders
Transponder: An automatic device that receives, amplifies, and retransmits a signal on a different frequency (see also broadcast translator).
• what is Moore's Law?
The prediction by Gordon Moore -cofounder of the Intel Corporation that the number of transistors on a microprocessor would double periodically -approximately every 18 months.
• Explain Superhyterodyne reciever.
Superhyterodyne system, the incoming signal is mixed with a local oscillator to produce sum and difference frequency components. The lower frequency difference component called the intermediate frequency (IF), is separated from the other components by fixed tuned amplifier stages set to the intermediate frequency. The tuning of the local oscillator is mechanically ganged to the tuning of the signal circuit or radio frequency (RF) stages so that the difference intermediate frequency is always the same fixed value.
• What are the different types of filters?
low pass, high pass, band pass, band stop, resonant
• What is impulse response?
Impulse response of a system is its output when presented with a very brief input signal, an impulse. A system in the class known as LTI systems (linear, time-invariant systems) is completely characterized by its impulse response. The Laplace transform of the impulse response function is known as the transfer function. It is usually easier to analyze systems using transfer functions as opposed to impulse response functions. The Laplace transform of a system's output may be determined by the multiplication of the transfer function with the input function in the complex plane, also known as the frequency domain. An inverse Laplace transform of this result will yield the output function in the time domain. To determine an output function directly in the time domain requires the convolution of the input function with the impulse response function.
• What do you mean by half-duplex and full-duplex communication? Explain briefly.
Half duplex - both sender & receiver can communicate with each other, but not simultaneously Full duplex - both sender & receiver can communicate with each other, simultaneous communication is also possible"
• What is RS in RS-232 ?
RS-232(Recommended Standard 232) is a standard for communication between devices, such as a modem and computer
• whats Farrady's law
Any change in the magnetic environment of a coil of wire will cause a voltage (emf) to be "induced" in the coil.The change could be produced by changing the magnetic field strength, moving a magnet toward or away from the coil, moving the coil into or out of the magnetic field, rotating the coil relative to the magnet, etc.
• What is Lenz law ?
When an emf is generated by a change in magnetic flux, the polarity of the induced emf is such that it produces a current whose magnetic field opposes the change which produces it.
• What is Transmission Frequency of Bluetooth, Wi-Fi and Wi-MAX ?
Bluetooth - 2.4 GHtz,
Wi-Fi - 2.4 Ghz to 5 Ghz
Wi-Max-10 to 66GHz"
• What type of architecture is used in 8085 microprocessor?
• How many states does signal has ?
There are 3 states in a signal: on state, off state, tri state
• which software is used to design a software IC using VHDL
• Why are nand gates and NOR gates called Universal gates
Becoz using these 2 gates any other type of gates can be made
• What is Vcc? Why is it called so
Vcc -Common collector voltage, plus collector supply line voltage in a common NPN circuit. Vcc is positive supply voltage for BJT collectors, and Vdd is +ve supply for FET drains. Vee For BJT emitters, and Vss for FET sources. "
• what is the difference between Mealy and Moore
In Mealy machines the o/p is a function of the current state and the inputs whereas In Moore machines the o/p a function of current state only
• what is 555 and why is it named so
555 Timer is used to produce accurate and stable time delays ranging from microseconds to hours.inside the 555 timer, there are 3 resistors used in series all the 3 resistors used are same and are 5k ohm resistors..so its called 555 timer..
• whats Shannon's source coding theorm
Source coding theorem is stated as follows:Given a discrete memoryless source of entropy H(p), the average code-word length L for any source encoding is bounded as L >= H(p)
• where is shannos/source coding used
This is basically used for Data Compression using different codes but following this rule.
• Difference between FIR and IIR filters
"Finite impulse response and infinite impulse response filters finite impulse response settles to zero in a finite number of sample intervals. This is in contrast to infinite impulse response (IIR) filters, which have internal feedback and may continue to respond indefinitely FIR filters are always stable but IIR may or may not be stable