Electrical Engineering Answers

Consider a continuous wave (single tone)

transmitted waveform of carrier frequency . The signal impinges on a target, moving

with radial velocity , and returns to the radar. The resulting signal, after down-

conversion from an IQ quadrature receiver, is given by

In the above expression, is the strength of the returned signal, is the positive

Doppler shift due to the target’s radial motion and t is the slow time. The signal over

a duration of T is digitized with a sampling frequency . Process the signal using

Fourier transform to obtain the correct estimate of the target velocity. Use the

values in the table below.

S. No. Parameters Values

1 Carrier frequency ( 5 GHz

2 Sampling frequency (.) 500 Hz

3 Dwell time (T) 1 second

4 Target return strength () 1 Volt

5 Radial velocity (,) 3 m/s

V=10 sin 2π100t

Draw a well-labelled diagram of the traverse section of a motor field winding showing the interpoles. What is the function of the interpoles?

6. Draw a picture of the following functions, defined over (−π, π): f(x) = x (π − |x|) g(x) = |x|(π − |x|) h(x) = x (π − x) k(x) = |x|(π − x)

A sequential circuit has two inputs, w₁ and w₂, and output, z. Its functon is to compare the input sequences on the two inputs. If w₁ = w₂ during any four consecutive clock cycles, the circuit produces z = 1; otherwise, z = 0. For example

w₁ : 0110111000110

w₂ : 1110101000111

z : 0000100001110

Derive a suitable circuit.

Justify the role of Zener diode work as voltage regulator (answer in detail)

In a p-n diode, if the doping concentration on the then-side is larger than the doping concentration on the p-side, which side has a larger depletion width? Justify

Consider a continuous wave (single tone)

transmitted waveform of carrier frequency . The signal impinges on a target, moving

with radial velocity , and returns to the radar. The resulting signal, after down-

conversion from an IQ quadrature receiver, is given by

In the above expression, is the strength of the returned signal, is the positive

Doppler shift due to the target’s radial motion and t is the slow time. The signal over

a duration of T is digitized with a sampling frequency . Process the signal using

Fourier transform to obtain the correct estimate of the target velocity. Use the

values in the table below.

S. No. Parameters Values

1 Carrier frequency ( 5 GHz

2 Sampling frequency (.) 500 Hz

3 Dwell time (T) 1 second

4 Target return strength () 1 Volt

5 Radial velocity (,) 3 m/s

Consider two radars. The first is a 3-GHz weather radar having a desired

unambiguous range of 300 km and unambiguous velocity of 50m/s. The second is.

10-GHz airborne radar having a desired unambiguous range of 100 km and

unambiguous velocity of 250 m/s. For each radar, is a 1 kHz PRF considered to be low

or high PRF?

Consider a 5GHz (C band) radar using a pulse repetition frequency of 3500

pulses per second. The radar collects 30 pulses of data. The slow time data sequence

is zero-padded and input to a 64-point DFT to compute the Doppler spectrum.

(a) What is Doppler frequency resolution in Hertz (with and without zero padding)?

(b) What is the spacing in meters per second (with and without zero padding)?

(c) What are the blind velocities of this radar?