fm station proposal

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Introduction FM radio broadcast is one of the main types of radio broadcasting. FM usually denotes frequency modulation. This frequency modulation usually takes place on VHF airwaves in a frequency range of 88 to !8 around the world e"cept #apan and $ussia. This following article shares precise information on FM radio broadcast. %o& 'nd out everything about FM radio broadcast whether its advantages or disadvantages right here. %ources have revealed that FM radio broadcasting is very popular especially in developed areas including (urope and )nited %tates because higher sound 'delity as well as stereo broadcasting certainly became quite familiar in this format *uring +,!s& (dwin H -rmstrong invented FM radio. He invented it to overcome the interference problem associated with -M radio broadcasting to which is relatively immune. oing further with the details on FM radio broadcast& we come up with the point that for accommodating an audio signal in FM radio& it does not require a bandwidth of /!! kH0. 1hat is all required is /! kH0 to ,! kH0 for a narrowband FM radio broadcast or FM signal. The /!! kH0 bandwidth enabled space for 234 kH0 signal deviation from the appointed frequency. Moreover& guard bands for minimi0ing or eliminatingad5acent channel interference. However& the greater or higher bandwidth enables to broadcast for a 4 kH0 bandwidth audio signal. Meanwhile the e"tra unused capacity is generally used for transmitting utility acts like background music for public areas& as well as 6% au"iliary signals.

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FM StationEngineering ProposalFM Station DesignFM Broadcast Design

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IntroductionFM radio broadcast is one of the main types of radio broadcasting. FM usually denotes frequency modulation. This frequency modulation usually takes place on VHF airwaves in a frequency range of 88 to 108 around the world except Japan and Russia. This following article shares precise information on FM radio broadcast. So, find out everything about FM radio broadcast whether its advantages or disadvantages right here.Sources have revealed that FM radio broadcasting is very popular especially in developed areas including Europe and United States because higher sound fidelity as well as stereo broadcasting certainly became quite familiar in this format. During 1930s, Edwin H Armstrong invented FM radio. He invented it to overcome the interference problem associated with AM radio broadcasting to which is relatively immune. Going further with the details on FM radio broadcast, we come up with the point that for accommodating an audio signal in FM radio, it does not require a bandwidth of 200 kHz. What is all required is 20 kHz to 30 kHz for a narrowband FM radio broadcast or FM signal. The 200 kHz bandwidth enabled space for 75 kHz signal deviation from the appointed frequency.Moreover, guard bands for minimizing or eliminating adjacent channel interference. However, the greater or higher bandwidth enables to broadcast for a 15 kHz bandwidth audio signal. Meanwhile the extra unused capacity is generally used for transmitting utility acts like background music for public areas, as well as GPS auxiliary signals.The problem of AM radio interference during nighttime was generally addressed in different way. The time when FM was first set up, the available frequencies were far greater or larger in comparison to those used for AM radio broadcast roughly around 100. Using these frequencies meant that even at far larger power, the range of a given FM radio broadcast or FM signal was much shorter, thus its market was more local than for AM radio. The reception range at night is the same as in the daytime. However, all new radios included both AM and FM tuners, FM became the dominant medium, especially in cities. Because of its greater range, AM remained more common in rural environments.

Design BackgroundThe to be established FM station, Rockstar Radio 94.7 MHz, is amusic/news/talkradio stationserving mainly inBo. Obrero, Davao City with a power of 20 000 watts. The station'sstudio, as well as the transmitter, will be assembled in the fifth floor of the College of Engineering building in the University of Southeastern Philippines. DXJC will operate 20 hours a day, from 4 oclock in the morning until midnight, 7 days a week.

1. name2. operating frequency3. operating power4. operating time5. classes of fm broadcast stations-class a

Design Concepta.) Frequency For the project, a frequency of 94.7 MHz is used. A channel at the middle part of Very High Frequency band is selected because it is commercially available and it is more convenient for listeners to tune their radios.b.) Type of ModuleSince the coverage area is relatively small, Rockstar Radio will broadcast in stereo where typically there is only onemicrophone, oneloudspeaker, or (in the case ofheadphonesand multiple loudspeakers) channels are fed from a commonsignalpath. In the case of multiple microphones the paths are mixed into a single signal path at some stage. Aside from mono being less expensive for recording and reproduction, recording is easy and only requires basic equipment.c.) Modulating Indexm=f/fmwhere: f=peak carrier frequencyfm=modulating frequencyfor commercial FM, f=75kHzfm=15kHzm=75/15m=5

d.) BandwidthB=2(m+1)*fmB=2(5+1)*15 kHzB=180 kHzGuard bands: 10 kHz at both ends, thereforeB=180 + 2(10)B=200 kHz

e.) Power AmplifierIn this design, we used a Class D power amplifier. The voltage mode Class D amplifier is defined as a switching circuit that results in the generation of a half-sinusoidal current waveform and a square voltage waveform. A series-tuned output filter passes only the fundamental frequency component to the load. Class D amplifiers suffers from losses due to a number of reasons: non-zero saturating resistance, finite switching speed and output capacitance of the devices. Class D power amplifiers are mainly used in the HF and VHF bands, sometimes output levels up to 1 kW. They are not preferred at the frequencies in the GHZ range, although this might change in the future, Class D operation with efficiency as high as 80% at 1GHZ has been reported. A unique aspect of Class D is that efficiency is not degraded by the presence of reactance in the load.

f.) Antenna PolarizationVertical polarization provides the best possible coverage for frequency modulated radio signals since most of the receivers utilize vertical antennas and the antenna design gives maximum radiation efficiency. The implementation of vertical polarization is implemented by using a half wave dipole antenna in an array system mounted on the vertical length of the tower with a 1 wavelength spacing between each element for maximum radiation efficiency.

g.) Station LocationThe station, as well as the transmitter, will be located at the fifth floor of the College of Engineering building in the University of Southeastern Philippines. The area of coverage will be mainly Bo. Obrero, Davao City with a land area of approximately 800,000 square meters. Below are the topographical map of Davao City and the elevation profile of Obrero, Davao City.

System of Designinga.) Block Diagram

i. The exciter is the most important part of an FM Transmitter because the FM signal is generated at this stage. It can operate as a low power standalone transmitter. The exciter section contains carrier oscillator, buffer amplifier, and reactance modulator.ii. After successful FM signal generation, the signal is split before being passed into the amplifier bank. This helps us ensure a low noise amplification and improved signal to noise ratio.iii. The various outputs from the splitter stage were directly coupled into an amplifier. A 1 kW Class C amplifier was used for this purpose. This provides the effective power boost needed for the transmission of the signal over a range.

iv. The combiner unit is a reciprocal of the splitter unit. It is made up to three combining stages. The first stage employs four sets of 6:1 combiners to yield four 6 kW signals. The second stage uses two sets of 2:1 combiners to two signals of 12 kW each while the third stage combines the two 12 kW signals to yield a 24 kW output.b.) AntennaThe antenna used in this design is an omnidirectional transmitting antenna. The antenna has a gain of 2.15 dB and an impedance of 50 ohms. Its grounding system is composed of metal clamps. The physical height of the antenna is 143 cm. Shown below are its vertical and horizontal patterns.

Frequency of transmission, f = 94.7 MHz=c/f =3x108/94.7x106 =3.168mPhysical antenna length, l=/4 =3.168/4 =0.7191mTherefore, length = 71.91 cm Bill of Materials

Item #QTYUnitDescriptionPriceAmount

1125FeetSAT-PAK COM RG 213 Coaxial Cable15,266.0815,266.08

22PcsLMR-400-75 type N male plugs and grounding6,600.006,600.00

31PcsBehringer Ultramizer Audio Processor4,400.004,400.00

42PcsSHURE SM574,356.004,356.00

51PcsAltec Lansing VS2621 Speakers2,350.002,350.00

62PcsTechno Tamashi TH-1049599.00599.00

71PcsALTO Equalizer 31 band mono4,500.004,500.00

81PcsMICKLE MT7-USB Mixing Console4,999.004,999.00

91SetBNC Connectors and Peripherals20, 000.0020, 000.00

101PcsBroadcom FM Broadcast Antenna 87-108MHz11,450.0011,450.00

112Pcs800 ft. 10-Gauge Bare Copper Grounding Wire8,404.0016,808.00

121PcsAirman Welder 350 amp 9.9 Generator250,000.00250,000.00

131PcsHP Envy Recline 27xt53,679.0053,679.00

141PcsAxel Oxygen 5 Broadcast Mising Console254,952.14254,952.14

151PcsArmstrong FM20000T2 20 kW FM Transmitter2692582.072692582.07

12monthsBuilding Rental, Power Consumption50,000.00600,000.00

TOTAL AMOUNT 3,922,541.29

FM Tower Construction and Materials500000500000

FM Station Studio Construction150,000.00150,000.00

6Employee Salary12,500.0075 000.00

Labor Cost 588,381.19

TOTAL INVESTMENT 10,160,922.48

Republic of the PhilippinesUniversity of Southeastern PhilippinesCOLLEGE OF ENGINEERINGObrero Campus, Davao City

BROADCAST ENGINEERING AND APPLIED ACOUSTICS

Rockstar Radio94.7 MHz

Submitted to:Engr. Joey Dela Cruz

Submitted By:Cedric D. ConolJoannacel A. Paraiso