Problem 1 two identical amplifiers with gain 65 db each are

Question

Problem 1: Two identical amplifiers with gain 6.5 dB each are placed in series.

a. Calculate gain of the series combination.

b. If the measured third order intercept of the series combination is +22.2dBm, calculate the third order intercept of each amplifier in dBm.

Problem 2: To reduce interference, an engineer suggests a filter be inserted between the antenna input and first stage of a receiver. The filter has a loss of 1.5 dB. If the noise figure of the receiver is 2.4 dB, calculate the noise figure of the filter/receiver combination. Remember that a passive device has noise figure equal to its loss.

Problem 3: A Tuned Radio Frequency receiver is designed with 6 identical stages of Amplifier/Filter between the input and the detector.

a. If the total gain between the antenna input and the detector should be 126 dB, what should the gain of each amplifier/filter be?

b. If each filter has a measured voltage response V_out/V_in = .9, what should the gain of each amplifier be in dB.

Problem 4: While attempting to reverse engineer a receiver, an engineer determines that when the received signal frequency is 4125 kHz and the image frequency is 22125 kHz. What would the IF frequency for this receiver be and why?

Problem 5: At the input of a receiver the carrier level is -116 dBm. Let the temperature be T = 270 K and the receiver bandwidth B = 75 kHz. Let the receiver Noise Figure be 8 dB.

a. Calculate the C/N ratio at the receiver antenna input in dB.

b. Calculate the C/N ratio at the detector in dB.

Answer 1

For the following numerical problem illustrated below, solve and provide solutions by exhibiting the calculation part. Q1: The two identical amplifiers having gain 6.5 dB each are placed in series. a) Compute gain of the series combination. b) If the measured IIIrd order intercept of the series combination is +22.2dBm, compute the third order intercept of each and every amplifier in dBm. Q2: To decrease interference, an engineer proposes a filter be inserted between the antenna input and first phase of a receiver. The filter consists of a loss of 1.5 dB. If the noise figure of the receiver is 2.4 dB, compute the noise figure of the filter or receiver combination. Keep in mind that a passive device consists of noise figure equivalent to its loss.