Design of Broadcast

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  • Topic: Radio, Frequency modulation, Broadcast engineering
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  • Published : December 15, 2012
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Frequency Modulation

Design of FM Broadcast Systems
ECE 211L Broadcast Engineering Laboratory

A system of modulation where the instantaneous frequency of the carrier and its rate of change varies in proportion to the instantaneous amplitude of the modulating signal.

The FM Broadcast Band
That portion of the radio frequency spectrum from 88 MHz to 108 MHz. The band is divided into 100 channels, starting at 88.1 MHz up to 107.9 MHz. Each channel is 200 kHz wide, designated by its carrier frequency. Co-located stations should be spaced at least Co800 kHz apart to avoid possible interference.

Classes of FM Broadcast Stations
Class-A Stations ClassA station authorized to have a transmitter power no more than 25 kW and an effective radiated power (ERP) not exceeding 125 kW. The minimum transmitter power shall be 10 kW. The antenna height is limited to 2,000 ft. above the average terrain. Class-A stations shall only be allowed in Metro Manila Classand Metro Cebu. Cebu.

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Classes of FM Broadcast Stations
Class-B Stations ClassA Class-B station shall have an authorized transmitter Classpower not exceeding 10 kW and an effective radiated power (ERP) not exceeding 30 kW. The minimum transmitter power shall be 1 kW. The antenna height is limited to 500 ft. above the average terrain.

Classes of FM Broadcast Stations
Class-D Stations ClassA Class-D station shall have an authorized transmitter Classpower not exceeding 10 W Educational stations shall be allowed to operate with a Class-D license. Class-

Class-C Stations ClassA non-commercial, community station having an nonauthorized radiated power not exceeding 1 kW.

Radio-Frequency Protection Ratios
All classes of FM stations shall be protected to the 1 mV/m or 60 dBu contour. The following ratios provide for the minimum separation between stations and protection of stations from interference: Frequency Spacing, kHz 0 200 400 R.F. Signal Ratio 60 dBu : 15 dBu 60 dBu : 33 dBu 60 dBu : 80 dBu

List of Requirements When Applying for a New FM Station
I. Congressional Franchise II. File a petition for a Certificate of Public Convenience (CPC) with the NTC. 1. Articles of Incorporation and By-Laws duly approved by the BySecurities and Exchange Commission (SEC). 2. List of present Officers and Board of Directors and the corporate corporate secretary's affidavit attesting to its present corporate structure. structure. 3. Duly accomplished information sheet of each and every member of the Board of Directors. 4. Audited financial statement of the corporation for the last three three (3) years and copy of income tax returns for the same year. 5. Economic viability study (for commercial stations), source of funds (for non-commercial stations). non-

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List of Requirements When Applying for a New FM Station
6. Technical feasibility study and engineering plans and diagrams (signed and sealed by an Electronics and Communications Engineer duly registered with the Philippine Regulation Commission). 7. Duly accomplished application for: a. Permit to Purchase Transmitter b. Construction Permit (Forms are available at NTC)

Pre-planning Considerations in the Design of FM Stations
Studio and Transmitter Site Selection Studio and Control Room Requirements Remote Studio Facilities (STL)

III. A Public Hearing shall be conducted. IV. The Commission shall render a decision on the petition.

Site Selection
Transmitter Site
The transmitter site is primarily considered due to its effect to existing stations located in the same area. Also, site selection is important because of the fact it will determine your coverage area (service area). The location should be chosen so that line-of-sight line- ofcan be obtained from the antenna over the general service area.

Remote Studio Facilities
In cases where the studio and the transmitter cannot be located in the same facility, or it is better for the transmitter to be located elsewhere (economically or technically),...
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