Principles of Electronic Communication Systems 4th. Edition by Louis E. Frenzel jr. | 9780073373850 | 73373850 | Holooly

Principles of Electronic Communication Systems

106 SOLVED PROBLEMS

Question: 13.4.3

In many cases, the antenna or other load impedance is not known. If it is not matched to the line, the line modifies this impedance so that the transmitter sees a different impedance. One way to find the overall impedance as well as the antenna or other load impedance is to measure the combined ...

Verified Answer:

One wavelength at 72 MHz is 984/72 = 13.67 ft. Tak...

Question: 13.4.2

An antenna is connected to the 24-ft 53.5-Ω RG-58A/U line described in Example 1. The load is 40 + j30 Ω. What impedance does the transmitter see? ...

Verified Answer:

The prime center is 53.5 Ω, as before. Before plot...

Question: 13.4.1

The operating frequency for a 24-ft piece of RG-58A/U coaxial cable is 140 MHz. The load is resistive, with a resistance of 93 Ω. What is the impedance seen by a transmitter? ...

Verified Answer:

The first step is to find the number of wavelength...

Question: 2.17

The upper and lower cutoff frequencies of a resonant circuit are found to be 8.07 and 7.93 MHz. Calculate (a) the bandwidth, (b) the approximate resonant frequency, and (c) Q. ...

Verified Answer:

a.

BW = f_2 - f_1 = 8.07 MHz - 7.93 M...

Question: 17.1

A satellite earth station is to be located at longitude 95° west, latitude 30° north. The satellite is located at 121° west longitude in geosynchronous orbit. Determine the approximate azimuth and elevation settings for the antenna. ...

Verified Answer:

a. Difference between longitude of satellite and l...

Question: 22.1

An RF voltmeter with a detector probe is used to measure the voltage across a 75-Ω resistive load. The frequency is 137.5 MHz. The measured voltage is 8 V. What power is dissipated in the load? ...

Verified Answer:

An RF power meter with a detector probe produces a...

Question: 22.2

If the forward power and reflected power in a circuit are known, the SWR can be calculated. If the forward power is 380 W and the reflected power is 40 W, what is the SWR? ...

Verified Answer:

SWR =

\frac{1 + \sqrt{P_{R}/P_{F}}} {1 –...

Question: 19.3

A measurement is made on a fiber-optic cable 1200 ft long. Its upper frequency limit is determined to be 43 Mbps. What is the dispersion factor d? ...

Verified Answer:

1 km = 3274 ft D = 1200 ft =

\frac{1200}{ 3...

Question: 19.2

A fiber-optic cable has a bandwidth rating of 600 MHz·km. What is the bandwidth of a 500-ft segment of cable? ...

Verified Answer:

1 km = 0.62 mi 1 mi = 5280 ft 1 km = 0.62(5280) = ...

Question: 19.1

The numerical aperture of a fiber-optic cable is 0.29. What is the critical angle? ...

Verified Answer:

NA = sin

θ_c

0.29 = sin

θ_c[...

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