Thursday, October 22, 2009

EI1302 (2 MARKS) UNIT II


ELECTRONIC AND INSTRUMENTATION

UNIT II

1. What is signal generator?

It is an instrument which provides several different output waveforms including sine wave, square wave, triangular wave,

2. What are the requirements of signal generator?

The requirement of signal generator is,

a) The output frequency of signal generator should be very stable

b) The amplitude of the output signal must be stable.

3 .What are the advantages of standard signal generator?

The advantages are,

a)The output is stable

b)The output voltage can be controlled according to the requirement.

4. Define duty cycle?

Duty cycle is defined as the ratio of average value of a pulse over one cycle to peak value.

5.Define risetime and fall time?

Rise time is the time required for the pulse to increase from 10% to 90% of its normal amplitude.

Fall time is the time required for the pulse to decrease from 90% to 10% of its maximum amplitude.

6.What are the requirements of pulse generator?

a)The pulse should have minimum distortion,

b)The pulse generator can be used to trigger pulses.

7.Define wave analyzer and name its types?

A wave analyzer is an instrument designed to measure the relative amplitudes of single frequency components in a complex or distorted waveform.

Its types are,

a)Frequency selective wave analyzer

b)Heterodyne wave analyzer

8.What is the principle of heterodyne wave analyzer?

It is a RF range analyzer works on the principle of mixing. In this type wave analyzer, the input signal is heterodyned to a higher intermediate frequency by an internal local oscillator.

9.Name the applications of wave analyzer?

Wave analyzer is used in

a)Fields of electrical measurement and sound,

b)Vibration analysis

10.What is spectrum analyzer?

Spectrum analyzer is an instrument which graphically provides energy distribution of a signal as a function of the frequency on its CRT.

11.What is meant by harmonic distortion?

The distortion caused due to non-linear behaviour of the circuit elements is called harmonic distortion.

12.What are the advantages of harmonic distortion analyzer?

a)The harmonic distortion generated within the instrument itself which may cause in total harmonic distortion measurement is very small and neglected.

b)The selectivity requirements are not severe because only the fundamental frequency component must be suppressed.

13.Write the advantages of audio frequency signal generator?

a)Stable and simple operation,

b)Low distortion,

c)Good amplitude stability

14. What is pulse preshoot?

The pulse pre shoot is the deviation prior to reaching the base line at the start of the pulse.

15.What is ringing?

Ringing is the positive and negative distortion excluding overshoot.

16.What is pulse repetition rate?

The pulse repetition rate is the reciprocal of pulse period and it is measured in termed in units of frequency.

17.What are the advantages of wide band sweep generator?

a)Very popularity used to determine the frequency response of the amplifiers and other systems.

b)A wide range of frequencies can be generated.

18.What is meant by settling time?

Settling time is the period needed for pulse ringing to be within a specified percentage if the pulse amplitude, measured from 90% point of the leading edge.

19.Define pulse drop or sag?

Sag is defined as the fall in pulse amplitude within time. Pulse rounding is the curved portion of the pulse at the leading and trailing edge.

20.What is meant by linearity?

Linearity of the pulse is the deviation of the edge from the straight line drawn through the10% and 90% points expressed as percentage of amplitude of pulse.

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