Telecommunications part 1 (Please show all work):
1. A signal level of 0.4μV is measured on the input to a satellite receiver. Express this voltage in terms of dBμV. Assume a 50-Ω system.
2. A microwave transmitter typically requires a +8dBm audio level to fully drive the input. If a +10dBm level is measured, what is the actual voltage level measured? Assume a 600-Ω system.
3. If an impedance matched amplifier has a power gain (Pout / Pin) of 15, what is the value of the voltage gain (Vout / Vin)?
4. Determine the deviation ratio for an FM system that has a maximum possible deviation of 5 kHz and the maximum input frequency is 3 kHz. Is this narrow- or wideband FM?
5. A receiver with a 10 MHz bandwidth has a S/N of 5dB and a sensitivity of -96dBm. Calculate the NF.
6. What is the dynamic range (in dB) for a 12-bit PCM system?
7. Calculate the number of bits required to satisfy a dynamic range of 48dB.
8. The transmit power for a digital communications device is 1 W. The data rate is 28.8kbps. Determine the energy per bit.
9. A 56kbps NRZ-L encoded data stream is used in a digital communication link. Determine the minimum bandwidth required for the communications link.
Telecommunications part 2 (Please show all work):
1. A balanced transmission line picks up an undesired signal with a 5 mW level. After conversion to an unbalanced signal using a center-tapped transformer, the undesired signal is 0.011μW. Calculate the common mode rejection ratio, CMRR.
2. A fast rise-time 10-V step voltage is applied to a 50-Ω line terminated with an 80-Ω resistive load. Determine the reflection coefficient Γ , EF and ER.
3. Calculate the ratio horizon for a 500-ft transmitting antenna and a receiving antenna of 20 ft. Calculate the required height increase for the receiving antenna if a 10% increase in the radio horizon were required.
4. An antenna has a maximum forward gain of 14dB at its 108-MHz center frequency. Its reverse gain is -8dB. Its bandwidth extends from 55 to 185 MHz, calculate a) the bandwidth and b) the F/B ratio of the antenna.
5. Calculate the effective radiated power (ERP) of an antenna with a gain of 5 at a power of 0.5 kW.
6. The antenna in question 5 above has a forward gain of 18dB and a reverse gain of 5dB, calculate the F/B ratio of this antenna.
7. A ship radio-telephone transmitter operates at 2738 kHz. At a distant point from the transmitter, the 2738 kHz signal has a measured field of 147mV/m. The second harmonic field at the same point is measured as 405 μV/m. How much has the harmonic emission been attenuated below the 2738 kHz fundamental?
8. Calculate the maximum usable range for a radar system with a PRT of 400 μs.
9. A green LED light source functions at a frequency of 5.7 x 1014 Hz, calculate its wavelength.