This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information. Skip to content Mind Sculpt.
Toggle navigation. Add a menu. Search for:. By : admin December 22, This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish.
Privacy Overview This website uses cookies to improve your experience while you navigate through the website. Privacy Overview. Other editions. Enlarge cover. Error rating book. Cookies are used to provide, analyse and improve our services; provide chat tools; and show you relevant content on advertising.
You can learn more about our use of cookies here Are you happy to accept cookies? You can learn more about how we plus approved third parties use cookies and how to change your settings by visiting the Cookies notice.
The choices you make here will apply to your interaction with this service on this device. Essential We use cookies to provide our services, for example, to keep track of items stored in your shopping basket, prevent fraudulent activity, improve the security of our services, keep track of your specific preferences such as currency or language preferences , and display features, products and services that might be of interest to you.
Because we use cookies to provide you our services, they cannot be disabled when used for these purposes. It communication electronics frenzel solution manual can achieve a communication electronics frenzel solution manual carrier suppression of 50 to 65 communication electronics frenzel solution manual dB. Format: PDF. Our interactive player communication electronics frenzel solution manual makes it easy to find solutions to Principles Of Electronic Communication Systems 3rd Edition problems you're working on - just go to the chapter for your book.
Eggleston Solution communication electronics frenzel solution manual Manual and Test bank communication electronics frenzel solution manual Introduction to Electronics: communication electronics frenzel solution manual A Basic Approach Peter communication electronics frenzel solution manual Basis Solution Manual communication electronics frenzel solution manual High-Frequency Magnetic communication electronics frenzel solution manual Components 2nd Ed.
Every effort is made to reduce the SWR by using impedance-matching circuits to ensure that maximum power is delivered to the load. Transmission lines, one-quarter or one-half wavelength long and either shorted or open, act like resonant or reactive circuits. At UHF and microwave frequencies where one-half wavelength this less than 1 ft, transmission lines are commonly used to replace conventional LC tuned circuits.
A shorted quarter wave and an open half wave act like a parallel resonant circuit. Both an open quarter-wave circuit and a shorted half-wave circuit act like a series resonant circuit. The velocity of propagation of a radio signal is slower in a transmission line than in free space. This difference is expressed as the velocity factor F for different types of lines. Coax has a velocity factor of 0. The velocity factor of open wire line or twin lead is in the 0. An antenna or aerial is one or more conductors used to transmit or receive radio signals.
A radio signal is electromagnetic energy made up of electric and magnetic fields at right angles to one another and to the direction of signal propagation. The polarization of a radio signal is defined as the orientation of the electric field with respect to the earth and is either vertical or horizontal.
The most common antenna is the half wave dipole or doublet that has a characteristic impedance of approximately 73 flat the center. The dipole has a bidirectional figure-eight radiation pattern and is usually mounted horizontally but may also be used vertically. A popular variation of the dipole is the folded dipole which is one-half wavelength long and has an impedance of Another popular antenna is the quarter-wave vertical.
The earth acts as the other quarter wave to simulate a half-wave vertical dipole. The quarter-wave vertical is referred to as a ground plane antenna. It is fed with coax with the center conductor connected to the antenna and the shield connected to earth ground, to an array of quarter- wave, wires m called radials, or to a large, flat, metal surface. The characteristic impedance of a ground plane is about It has an omni directional radiation pattern that sends or receives equally well in all directions.
A directional antenna is one that transmits or receives over a narrow range in only one direction. Directional antennas made up of two or more elements focus the radiation into a narrow beam, thus giving the antenna gain. The gain of the, antenna is the power amplification resulting from the concentration of power in one direction. The gain may be expressed as a power ratio or in decibels.
The effective radiated power ERP of an antenna is the power input multiplied by the antenna power gain. Directional antennas with two or more elements are caIled arrays.
There are two types of arrays: parasitic and driven. Parasitic elements called reflectors and directors when spaced parallel to a half wave dipole driven element help focus the signal into a narrow beam.
The measure of the directivity of an antenna is the beam width or beam angle measured in degrees. Driven arrays consist of two or more half wavelength elements, each receiving power from the transmission line. The three most popular driven arrays are the collinear, end-fire, and broadside. A widely used driven array is the log periodic antenna which exhibits gain, directivity, and a wide operating frequency range.
A radio wave propagates through space in one of three ways: ground wave, sky waves, or direct waves. The ground or surface wave leaves the antenna and follows the curvature of the earth. The ground wave is only effective on frequencies below 3 MHz. The skywave propagates from the antenna upward where it is bent back to earth by the ionosphere. The ionosphere is a portion of the earth's atmosphere 30 to mi above the. The ionosphere is made up of three layers of different ionization density: the D, E, and F layers.
The F layer is the most highly ionized and causes refraction or bending of radio waves back to earth. The refraction of the ionosphere causes a radio signal to be bent back to earth with little or no attenuation long distances from the transmitter. This is known as a skip or hop. Multiple skips or hops between the ionosphere and earth permit very long distances, even worldwide, communications. This effect is useful over the 3- to MHz range. At frequencies above 30 MHz, propagation is primarily by the direct or space wave which travels in a straight line between transmitting and receiving antennas.
This is known as line-of-sight communications. Radio waves ate easily blocked or reflected by large objects. The communications distance at VHF, UHF, and microwave frequencies is limited to the line-of-sight distance between transmitting and receiving antennas. The line-of-sight distance D is limited by the curvature of the earth and is dependent upon the heights h, and h, of the transmitting and receiving antennas, respectively.
To extend transmission distances at VHF, UHF, and microwave frequencies, relay stations known as repeater stations receive and retransmit signals. A line 4 in. A coax line has a shield braid with an inside diameter of 0. A coax bas a antenna load. The maximum voltage along a transmission line is V, and the minimum voltage is 90V. The reflection coefficient of a transmission line is 0.
A transmission line bas an SWR of 1. The power applied to the line, is 90 W. An open transmission line 6 in. A coax bas a velocity factor of 0. A radio wave has its magnetic field horizontal to the earth. List two basic types of antenna arrays. List three kinds of driven arrays. Yagis and driven arrays may be operated either horizontally or vertically.
A quarter-wavelength of coax with a velocity factor of 0. List the three paths that a radio signal may take through space. Radio waves are easily reflected by large objects. The ionosphere reflects radio waves.
Q section, matching stub Microwaves are radio signals in the frequency range from I to GHz. The RF spectrum below UHF is mostly already fully occupied leaving little or no room for the growth of new radio services. At microwave frequencies, tremendous bandwidth is available for new radio services as well as for wide-bandwidth signals such as TV, multiplexed signals, or computer data. The microwave frequencies are used primarily for telephone communications, radar, and satellite communications.
Other microwave applications include cable TV, space communications, radio astronomy, and heating. The primary benefit of microwaves is wide bandwidth availability. The main disadvantages of microwaves are that they are limited to line-of-sight transmission distances, conventional components are not usable, and circuits are more difficult to analyze and design. Balanced transmission line is not used for microwaves because of radiation losses.
Coaxial cable is not used because of its high attenuation. The preferred transmission line for microwaves is waveguides. Because of the short physical length of transmission lines at microwave frequencies, quarter- and half- wave lines are commonly used for tuned circuits and filters.
Two printed circuit board implementations of transmission lines, called stripline and microstrip, are widely used to create resonant circuits and filters. A waveguide is a hollow metal pipe with a circular or rectangular cross section used for carrying microwave signals from one place to another. A waveguide acts like a high-pass filter, passing all frequencies above its cut-of frequency and rejecting those below it.
The cutoff frequency fco of a waveguide depends upon its physical size. The microwave signal carried by a waveguide is made up of electric E and magnetic H fields that bounce off the walls of the waveguide as they propagate along its length. The modes of a waveguide describe the various patterns of electric and magnetic fields that are possible. A transverse electric TE mode is one where the electric field is transverse or perpendicular to the direction of propagation.
A transverse magnetic TM mode is one where the magnetic field is perpendicular to the direction of propagation. Half-wavelength sections of waveguides with shorted or closed ends are known as resonant cavities since they "ring" or oscillate at the frequency determined by their dimensions. Cavity resonators are metallic chambers of various shapes and sizes that are used as parallel-tuned circuits and filters.
They have a Q of up to 30, Point-contact and Schottky or hot-carrier diodes are widely uses as mixers in microwave equipment as they have low capacitance and inductance. Varactor diodes are widely used as microwave frequency multipliers. Multiplication factors of 2 and 3 are common with power levels up to 20 Wand efficiencies up to 80 percent. Step-recovery or snap-off diodes are also widely used as frequency multipliers with multiplication factors up to 10, power ratings up to 50 W.
A Gunn diode is a microwave semiconductor device used to generate microwave energy. When combined with a microstrip, stripline or resonant cavity, simple low power oscillators with frequencies up to 50 GHz are easily implemented. Both are used in microwave oscillators. A klystron is a vacuum tube used for microwave amplification and oscillation. Klystrons use a cavity resonat or to velocity modulate an electron beam which imparts energy to another cavity, producing power amplification.
Klystrons are available which produce from a few to many thousands of watts. A single-cavity reflex klystron is used as a microwave oscillator.
Klystrons are being gradually replaced by Gunn diodes and traveling-wave tubes. A magnetron is a diode vacuum tube used as a microwave oscillator in radar and microwave ovens to produce powers up to the megawatt range. In a magnetron, a strong magnetic field creates circular paths of electron flow to excite cavities into oscillation. A traveling-wave tube TW T is a microwave power amplifier with very wide bandwidth. A microwave signal applied to a helix around the TW T produces velocity and density modulation of the electron beam over a long distance which induces a higher-power signal in the helix.
The most commonly used microwave antenna is the horn, which is essentially a rectangular waveguide with a flared end. A pyramidal horn flares in both waveguide dimensions. A sectoral horn flares in only one dimension. A parabolic or dish-shaped reflector is used with most microwave antennas to focus the RF energy into a narrow beam and increase gain. The parabolic reflector usually has a diameter that is no less than 10 wavelengths at the operating frequency.
The gain and directivity of a parabolic reflector antenna is directly proportional to its diameter. Parabolic reflector antennas are fed by placing a horn antenna at the focal point or by placing the horn at the center of the reflector and placing a small reflector at the focal point.
The latter is known as Cassegrain feed. A helical antenna is made up of six to eight turns of heavy wire or tubing to form a coil or helix.
It is fed with coax and is backed up with a reflector. Helical antennas produce circular polarization where the electric and magnetic fields rotate. The polarization may be right-hand or left-hand depending upon the direction in which the helix is wound. Helical antennas can receive either vertically or horizontally polarized signals but can only receive a circularly polarized signal of the same direction.
A popular omnidirectional microwave antenna is the bicone. List seven reasons why microwaves are more difficult to work with than lower frequency signals. List four popular uses for microwaves. Name four techniques that have helped squeeze more signals into the given spectrum. The TV channels 2 to 13 occupy a total bandwidth of about 72 MHz. Twin lead is not used at microwave frequencies. A rectangular waveguide has a width of 1. A waveguide has a cutoff frequency of 5 GHz.
It will pass a signal of 8 GHz. It will pass a signal of 3 GHz. List three reasons why conventional diodes and transistors do not work in the microwave region. Klystrons can be used as amplifiers or oscillators.
A magnetron operates as an amplifier. A horn antenna is six wavelengths long at 8 GHz. The width of a horn antenna is 8 cm. The height is 6 cm. The operating frequency is 8 GHz. A parabolic reflector antenna has a diameter of 9 m. The frequency of operation is 8 GHz. A helical antenna will receive either vertical or horizontally polarized signals.
Federal Communications Commission 7. LCR H, E TEO,1 P-type silicon, tungsten whisker Schottky barrier, or hot carrier Gunn Gunn diodes, TWTs Cassegrain A satellite is a physical object that orbits a celestial body.
A communications satellite containing electronic equipment acts as a repeater or relay station between two earth stations.
The basic component of a communications satellite is a receiver-transmitter combination called a transponder. A satellite stays in orbit because the gravitational pull of the earth, is balanced by the' centripetal force of the revolving satellite. Satellite orbits about the earth are either circular or elliptical. A satellite that orbits directly over the equator 22, mi from earth is said to be in a geostationary orbit. It revolves in synchronism with the earth's rotation, so it appears to be stationary when seen from points on the earth.
A satellite is stabilized in orbit by spinning it on its axis or building in spinning flywheels for each major axis roll, pitch, yaw. Attitude adjustments on a satellite are made by firing small jet thrusters to change the satellite's position or speed. The location of a satellite is determined with latitude and longitude measurements that designate a point on the earth subsatellite point SSP directly below the satellite.
Azimuth and elevation angles determine where to point an earth station so that it intercepts the satellite. Satellites are launched into orbit by rockets that give them vertical as well as forward motion. A geosynchronous satellite is initially put into an elliptical orbit where its apogee is 22, mi high.
The apogee kick motor is then fired to put the satellite into its final circular geostationary orbit. Many satellites are put into orbit by launching them from NASA's space shuttle. Most satellites operate in the microwave region. Microwave satellites operate on assigned frequency bands designated by a letter. Common communications satellite bands are the C 3. Satellite bands are typically MHz wide and are divided into 12 segments, each 36 MHz wide.
A transponder is used to cover each segment. Frequency reuse is a technique that allows two sets of transponders to operate on the same frequency, thus doubling channel capacity.
The two sets of channels use antennas of different polarizations to prevent interference with one another. Spatial isolation is another technique for frequency sharing.
It uses highly directional spot-beam antennas to prevent interference between stations on the same frequency. The main subsystems in a satellite are the communications; power; telemetry, tracking; and control TIC ; propulsion; attitude stabilization; and antenna subsystems.
A transponder consists of a low-noise amplifier LNA that receives and amplifies the up-link signal, a mixer that converts the signal to another lower frequency, and a high-power amplifier that retransmits the signal on its new down-link frequency. Double-conversion transponders use two, mixers, one to translate the up-link signal to an IF where it is amplified and filtered, and another to translate the signal to its final down-link frequency.
Regenerative transponders demodulate the up-link signal to recover the baseband signals and then use them to remodulate a downlink transmitter. This improves the SIN ratio. In a broadband transponder, a single mixer converts all channels within the MHz bandwidth simultaneously to their downlink frequencies. These are selected by channel bandpass filters and then amplified by individual power amplifiers. In a channelized transponder, each channel has its own LNA, bandpass filters, mixer, and high-power amplifier.
The power subsystem consists of solar panels, batteries, dc-to-dc converters, and regulators. The solar panels convert sunlight into de power to operate all satellite electronics and to charge the batteries that take over when sunlight is blocked. The TTC subsystem contains a receiver that picks up commands from a ground station and translates them into control signals that initiate some action on board.
The telemetry system monitors physical conditions within the satellites and converts them into electrical signals that are transmitted back to earth. The propulsion system consists of the apogee kick motor that puts the satellite into final orbit and the jet thrusters that are used for positioning and attitude control.
The stabilization subsystem for attitude control consists of spin components or three-axis flywheel gyros. The antenna system consists of one or more highly directional horn or parabolic antennas and an omnidirectional TTC antenna.
The transmit subsystem takes the baseband voice, video, or computer data signals: multiplexes them; and uses the composite signal to modulate a carrier. An up converter translates the signal to its final up-link frequency before it is amplified and transmitted. Transistor power amplifiers are used in low-power earth stations; klystrons are used in high-power narrowband stations; and TWTs are used in high-power broadband stations.
Earth stations feature large- parabolic dish antennas with high gain and directivity for receiving the weak satellite signal. The receive subsystem in an earth station amplifies the signal with an LNA and then separates the channels with bandpass filters. Down conveners translate the signals to a lower IF where they are demodulated and demultiplexed. The GCE in an earth station interfaces the baseband signals to the transmit and receive subsystems.
The receive GCE performs demodulation and demultiplexing. The transmit GCE performs modulation and multiplexing.
The most common application for satellites is communications. Another major use of satellites is surveillance and reconnaissance. Film cameras, TV cameras, infrared sensors, and radars are all used to observe a variety of conditions on earth from surveillance satellites.
Satellites playa major role in military and defense systems not only for communications but also for surveillance. The satellite Global Positioning System GPS makes accurate navigation possible anywhere on earth with a low-cost microwave receiver. Name two ways satellites are stabilized in space. List the three main functions of a transponder.
List the three main types of power amplifiers used in earth stations. All earth stations contain telemetry, control, and instrumentation subsystems. Name four types of surveillance sensors. What are the name and the purpose of the satellite system developed by the military? Name three uses for surveillance satellites. TWT Data communications is the transmission and reception of binary data between computers and other digital equipment.
The earliest form of electronic communications, the telegraph, was a type of data communications. Turning a carrier off and on in a code of dots and dashes is a kind of data communications known as continuous wave CW. Teletype is a form of telegraph that uses the 5-bit Baudot code to transmit between typewriters like units. The two main methods of data transmission are serial and parallel. In serial transmission, each bit is transmitted sequentially.
In parallel transmission, all bits are transmitted simultaneously. Serial transfers are slower than parallel transfers but require only a single line or channel. Parallel transfers require multiple channels of lines called a bus. Baud rate is the number of symbol changes per second. A symbol is an amplitude, frequency, or phase change. The channel-or bit-rate capacity of a channel is directly proportional to the channel bandwidth and the time of transmission.
The, bit rate is higher than the baud symbol rate if multiple-level symbol encoding is used. The two methods of data transmission are asynchronous and synchronous. In asynchronous transmission, data is sent one character at a time with start and stop bits.
In synchronous transmission, data is sent as a continuous block of multiple characters framed with synchronization characters. Synchronous transmission is faster than asynchronous transmission. In data communications, a binary 1 is referred to as a mark and a binary 0 as a space. Signals, whether voice, video, or binary, transmitted directly over a cable are known as baseband signals. Voice and video signals are analog but may be converted to digital for data communications transmission.
Signals that involve a modulated carrier a called broadband signals. Communications of binary data signal over the telephone network which is designed for analog signals is made possible by using a modem.
A modem is a modulator-demodulator unit that converts digital signals to analog and vice versa. Frequency-shift keying uses two frequencies for binary 0 and 1 and Hz or and kHz.
It operates at speeds of baud or less. Binary PSK is generated by a balanced modulator. Binary PSK is demodulated by a balanced modulator. To properly demodulate BPSK, the carrier at the demodulator must have exactly the same phase as the transmitting carrier. A special carrier recovery circuit in the receiver produces the correct phase carrier from the BPSK signal. Differential PSK eliminates the need for a special reference phase carrier by using a coding technique where the phase of each bit is referenced to the previous bit.
Quadrature PSK uses four equally spaced phase shifts of the carrier to represent two bits dibit. In 8-PSK, 3 bits are coded per phase change. In PSK, 4 bits are coded per phase change.
Thus the bit rate is 3 or 4 times the symbol rate change or baud rate. Each of the eight possible 3-bit combinations is represented by a unique phase and amplitude signal. A protocol is a rule or procedure that defines how data is sent and received. Protocols include "handshaking" signals between the transmitter and receiver that indicate the status of each.
The Xmodem protocol is widely used in personal computers. In synchronous communications, a variety of special characters are sent before and after the block of data to ensure that the data is correctly received.
Bit errors that occur during transmission are caused primarily by noise. The ratio of the number of bit errors that occur for a given number of bits transmitted is known as the bit error rate BER. Amazon Music Stream millions of songs. Read more Read less. Thanks for telling us about the problem. Page 1 of 1 Start over Page 1 of 1. Sign in to shop, frejzel, or access your account commuication. If you are a seller for this product, would you like to suggest updates through seller support?
In addition, it discusses antennas and microwave techniques at a technician level and covers data communication techniques modems, local area networks, fiber optics, satellite communication and advanced applications cellular telephones, facs This text introduces basic communication concepts and circuits, including modulation techniques, radio transmitters and receivers. Amazon Second Chance Pass it on, trade it in, give it a second life.
Other books in this series. Oct 09, Hayyan Pantaran rated it it was amazing. Want to Read Currently Reading Read. Books by Louis E. All shipping options assumes the product is available and that it will take 24 to 48 hours to process your order prior cojmunication shipping.
0コメント