Interview Questions- MBA Admissions- Job Interviews
- Electronics and Communication, Applied Electronics
• Distinguish between Angle modulation and Amplitude modulation.
In amplitude Modulation as the amplitude of given signal varies, the amplitude of carrier signal also varies in the same way.In angle modulation, the frequency or phase may vary according to the amplitude of given signal"
• What is Biasing?
Biasing is a process of connecting dc voltage to a device by which we can select the operating point of the device. by biasing actually we select the operating point of the device.
• What do you mean by 3 dB cutoff frequency? Why is it 3 dB, not 1 dB?
3db implies 70%(o.7o7) of the power,i'e we r interested to consider the bandwidth range from peak to 70% b'coz uptp 70% its reliable.hence 3db is called as half power freq. 3db value is the mean square value which is 70% of the maximum value.
• What is meant by pre-emphasis
Pre-emphasis -Improving the signal to noise ratio by increasing the magnitude of higher frequency signals with respect to lower frequency signal"
• What is meant by de-emphasis?
De-emphasis-Improving the signal to noise ratio by decreasing the magnitude of higher frequency signals with respect to lower frequency signals"
• What is sampling theorem?
It is defined as the sampling frequency should be greater than or equal to twice the sampling frequency then we can generate the original signal if the condition does not satisfy we get the signal in the distorted mannerit is given as ( fs >/ 2 fs)
• Explian FIR filters
Finite impulse response (FIR) filter is a type of a digital filter. The impulse response, the filter's response to a Kronecker delta input, is 'finite' because it settles to zero in a finite number of sample intervals. This is in contrast to infinite impulse response filters which have internal feedback and may continue to respond indefinitely.
• Quote few examples of FIR Filters
A FIR filter has a number of useful properties which sometimes make it preferable to an infinite impulse response filter. FIR filters: Are inherently stable. This is due to the fact that all the poles are located at the origin and thus are located within the unit circle. Require no feedback. This means that any rounding errors are not compounded by summed iterations. The same relative error occurs in each calculation. They can be designed to be linear phase, which means the phase change is proportional to the frequency.
• What are IIR filters
Infinite impulse response (IIR) is a property of signal processing systems. They have an impulse response function which is non-zero over an infinite length of time. The simplest analog IIR filter is an RC filter made up of a single resistor (R) feeding into a node shared with a single capacitor (C). This filter has an exponential impulse response characterized by an RC time constant.
• what are Asynchronous transmission
Asynchronous transmission uses start and stop bits to signify the beginning bit ASCII character would actually be transmitted using 10 bits e.g.: A "0100 0001" would become "1 0100 0001 0". The extra one (or zero depending on parity bit) at the start and end of the transmission tells the receiver first that a character is coming and secondly that the character has ended. This method of transmission is used when data is sent intermittently as opposed to in a solid stream. In the previous example the start and stop bits are in bold. The start and stop bits must be of opposite polarity. This allows the receiver to recognize when the second packet of information is being sent.
• what are Synchronous transmission
Synchronous transmission uses no start and stop bits but instead synchronizes transmission speeds at both the receiving and sending end of the transmission using clock signals built into each component. A continual stream of data is then sent between the two nodes. Due to there being no start and stop bits the data transfer rate is quicker although more errors will occur, as the clocks will eventually get out of sync, and the receiving device would have the wrong time that had been agreed in protocol (computing) for sending/receiving data, so some bytes could become corrupted (by losing bits). Ways to get around this problem include re-synchronization of the clocks and use of check digits to ensure the byte is correctly interpreted and received.
