Electrical Engineering Answers

1.  An activated sludge system has a flow of 4000 m³/day with X = 4000 mg/L and S₀ = 300 mg/L. From pilot plant work the kinetic constants are Y =0.5, μˆ =3 d−1, K_S =200 mg/L. We need to design an aeration system that will remove 90% of the BOD5. Specifically, we need to know (a) the volume of the aeration tank; (b) the sludge age; (c) the amount of waste activated sludge.

What is the approximate velocity resolution that can be provided by a 1-GHz air-search radar in which the antenna with a 5-deg azimuth beamwidth scans at 15 rpm in azimuth? Assume coherent integration over the beam dwell time.

A highway police radar operating at 10 GHz observes a Doppler shift of 1,500 Hz when the radar is pointed at a moving car. What is the radial speed of the car toward the radar in miles per hour?

A CW waveform expressed as Ae^ ' at the radar antenna terminals is transmitted. What is the expression at the same antenna terminals for the received signal of amplitude B from a point target at range R?

(a) How many samples per second would be required for unambiguous sampling of a range-extended echo signal from a coherent radar system if the receiver were matched to the transmitted pulse duration of 2.0us? (b) What is the equivalent sample separation in target slant range?

Which of the following signals could be accurately represented in complex form by (1.4): (a) a 10us video pulse (no RF carrier), (b) a 10-Hz to 20-kHz audio signal, or (c) a 2- ns RF echo pulse from a 10-GHz radar?

Two point targets are separated by 3m in slant range, (a) What radar bandwidth is required to resolve the two targets? (b) If the radar is a monotone pulse radar, what should be the maximum transmitted pulse duration? 

Describe method of improving string efficiency?

i) the advantage and disadvantage of DC and ac transmission system

ii) the advantage of using high transmission voltage

Determine the voltages at all nodes and the currents through all branches. The minimum value of β is specified to be 20.