Regulating Broadcasting
Overview of the technical specifications that make up the U. S. broadcast spectrum
Regulating Broadcasting
• FCC derives its power from – The Communications Act of 1934– The Telecommunications Act of 1996– Other amendments to these acts
• Satellite Communications Act
• Children’s Television Rules
Regulating Broadcasting
• In order to license and regulate an industry some industrial policy needs to be developed that follows – The guidelines outlined in the legislative acts– Standard procedures that everyone can follow– A systems process so technology can be applied
as efficiently as possible
Regulating Broadcasting
• Broadcasting uses a series of frequencies and we call those frequencies allocated to stations CHANNELS
• Channels are part of the spectrum allocation process
• Different parts of the spectrum are used for different purposes
Regulating Broadcasting
• Broadcasting - to be useful to every potential user of the spectrum - needs to have standards applied to – The transmission of signals– The reception of signals– The use of the spectrum
Regulating Broadcasting
• Terminology used– Frequency - the wavelength of the channel– Frequency (response) - the frequencies
broadcast that affect the quality of the programs– Amplitude - how the signal is modulated – Carrier wave - the frequency used to transmit– Hertz - the measure of frequency (1 HZ = 1
cycle per second)
Regulating Broadcasting
• Modulation methods used– Amplitude modulation - the audio portion of
the program is superimposed upon the carrier– Frequency modulation - the carrier is made to
oscillate in proportion to the program audio– Pulse code modulation - the amplitude is turned
on and off to represent the digital words transmitted
Regulating Broadcasting
• Standards– AM - Medium wave transmitting stations use amplitude
modulation– FM - VHF wave transmitting stations that use
frequency modulation– TV - VHF and UHF transmitting stations that use
NTSC standards (AM for the video picture and FM for the audio portion)
– DTV - VHF and UHF transmitting stations using 8 VSB (vestigal side band) modulation, MPEG 2 compression
Regulating Broadcasting
• More Standards– DTV standards
• 480 Interlace - 480 lines X 640 pixels odd and even scan lines interlace
• 480 Progressive - 480 lines X 640 pixels with lines scanned progressively
• 720 - 720 lines X 1280 pixels either I or P
• 1080i - 1080 lines X 1920 pixels I (ATSC standard)
Regulating Broadcasting
• The electromagnetic spectrum– 300,000 HZ to 3 MHZ (medium wave)
• 107 AM Channels
• Air and Marine, SOS and Ham radio
- 3 MHZ to 30 MHZ (shortwave)• International Shortwave, military, Ham
Regulating Broadcasting
• The electromagnetic spectrum– VHF (Very High Frequency Band)
• 30 MHZ to 300 MHZ - – 100 FM channels, VHF TV 2 through 13, police
– UHF (Ultra High Frequency)• 300 MHZ to 3000 MHZ
– UHF TV 14-72, radar and weather satellites
Regulating Broadcasting
• The electromagnetic spectrum– SHF (Super High Frequency Band)
• 3000 MHZ to 3 GHZ– Ku and C band communication satellites, Satellite radio,
microwave relay, air navagation, radar
– EHF (Extremely High Frequency Band)• 3 GHZ to 300 GHZ
– Military communications and future expansion
Regulating Broadcasting
• Radio Classification– AM (Standard Broadcast Band)
• 107 Channels between 530KHZ and 1705 KHZ– 60 Clear Channels - Class A (high power)
– 41 Regional - Class B (medium power)
– 6 Local Channels - Class C (low power)
• Each station has a 10 KHZ bandwidth
Regulating Broadcasting
• Radio Broadcasting– FM (authorized in 1945)
• 100 Channels between 88.0 MHZ and 108 MHZ– 80 Channels between 92 and 108 MHZ commercial
– 20 Channels between 88 and 92 MHZ educational
• Each channel is 200 KHZ wide and provides for the ability to multiplex transmission (FM Stereo)
– Power levels are classified A (lowest), B (medium) C (highest) and new D (low power FM)
Regulating Broadcasting
• Television Broadcasting– VHF - Channels 2 - 13
• 54 MHZ to 216 MHZ spectrum– Each TV channel is 6 MHZ wide
– UHF - Channels 14 - 72• 470 MHZ to 890 Mhz spectrum
– DTV - Both VHF and UHF– Each channel is 6 MHZ and uses MPEG 2 compression
with 8 VSB modulation
Regulating Broadcasting
• Other approved broadcasting services– DBS - Direct Broadcast Satellite
• TV service with satellite to home transmission– Using the DVB-2 modulation system capable of both
digital standard and HD signals in 12.75 to 14.5 GHZ band
– Satellite Radio• Audio service with satellite to car/home
transmission– Uses ACC coding in the S Band in the 2.332 to 2.345
GHZ band