Electrical Engineering Answers

What does a high value for signal-to-noise power ratio imply? How about a low signal-to-noise power ratio? 

The circuits in a superheterodyne receiver have the following gains: RF amplifier, 8 dB; mixer, -2.5 dB; IF amplifier, 80 dB; demodulator, -0.8 dB; audio amplifier, 23 dB. What is the total gain? 

The signal input power to a receiver is 6.2 nW. The noise power is 1.8 nW. What is the S/N ratio? What is the S/N ratio in decibels? 

 A receiver with a 75-Ω input resistance operates at a temperature of 31°C. The received signal is at 89 MHz with a bandwidth of 6 MHz. The received signal voltage of 8.3 μV is applied to an amplifier with a noise figure of 2.8 dB. Find (a) the input noise power, (b) the input signal power, (c) S/N, in decibels, (d) the noise factor and S/N of the amplifier, and (e) the noise temperature of the amplifier. 

An RF amplifier has an S/N ratio of 8 at the input and an S/N ratio of 6 at the output. What are the noise factor and noise figure?

What is the average noise power of a device operating at a temperature of 90°F with a bandwidth of 30 kHz? 

The bandwidth of a receiver with a 75-Ω input resistance is 6 MHz. The temperature is 29°C. What is the input thermal noise voltage?

what is the circuit open noise voltage across a 100-k resistor over the frequency range of direct current to 20 kHz at room temperature (25°C)? 

An electric heater carries 12A at 110V, is submerged in 22.5lbs of water

for 30minutes. What will be the final temperature of the water if its initial

temperature is 35°F?