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CATV CHANNEL CHART OF VIDEO FREQUENCIES
CHANNEL #
NORMAL ICC HRC
(MHz) (MHz) (MHz)
2 2 55.25 55.25 54
3 3 61.25 61.25 60
4 4 67.25 67.25 66
5 5 77.25 79.25 78
6 6 83.25 85.25 84
7 7 175.25 175.25 174
8 8 181.25 181.25 180
9 9 187.25 187.25 186
10 10 193.25 193.25 192
11 11 199.25 199.25 198
12 12 205.25 205.25 204
13 13 211.25 211.25 210
0 A-2 109.25 109.25 108
1 A-1 115.25 115.25 114
14 A 121.25 121.25 120
15 B 127.25 127.25 126
16 C 133.25 133.25 132
17 D 139.25 139.25 138
18 E 145.25 145.25 144
19 F 151.25 151.25 150
20 G 157.25 157.25 156
21 H 163.25 163.25 162
22 I 169.25 169.25 168
23 J 217.25 217.25 216
24 K 223.25 223.25 222
25 L 229.25 229.25 228
26 M 235.25 235.25 234
27 N 241.25 241.25 240
28 0 247.25 247.25 246
29 P 253.25 253.25 252
30 Q 259.25 259.25 258
31 R 265.25 265.25 264
32 S 271.25 271.25 270
33 T 277.25 277.25 276
34 U 283.25 283.25 282
35 V 289.25 289.25 288
36 W 295.25 295.25 294
37 AA 301.25 301.25 300
38 BB 307.25 307.25 306
39 CC 313.25 313.25 312
40 DD 319.25 319.25 318
41 EE 325.25 325.25 324
42 FF 331.25 331.25 330
43 GG 337.25 337.25 336
44 HH 343.25 343.25 342
45 II 349.25 349.25 348
46 JJ 355.25 355.25 354
47 KK 361.25 361.25 360
48 LL 367.25 367.25 366
49 MM 373.25 373.25 372
50 NN 379.25 379.25 378
51 00 385.25 385.25 384
52 PP 391.25 391.25 390
53 QQ 397.25 397.25 396
54 RR 403.25 403.25 402
55 SS 409.25 409.25 408
56 TT 415.25 415.25 414
57 UU 421.25 421.25 420
58 VV 427.25 427.25 426
59 WW 433.25 433.25 432
60 W + 439.25 439.25 438
61 W +1 445.25 445.25 444
62 W +2 451.25 451.25 450
63 W +3 457.25 457.25 456
64 W +4 463 25 463.25 462
65 W +5 469.25 469.25 468
66 W +6 475.25 475.25 474
67 W +7 481.25 481.25 480
68 W +8 487.25 487.25 486
69 W +9 493.25 493.25 492
70 W +10 499.25 499.25 498
|
TV Channel Frequency
Chart
|
Western European (E)
Channels |
|
Japanese |
|
South African Channels |
Chan
2
3
4
S-3
S-4
S-5
S-6
S-7
S-8
S-9
S-10
5
6
7
8
9
10
11
12
S-11
S-12
S-13
S-14
S-15
S-16
S-17
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69 |
BW(MHz)
47-54
54-61
61-68
118-125
125-132
132-139
139-146
146-153
153-160
160-167
167-174
174-181
181-188
188-195
195-202
202-209
209-216
216-223
223-230
230-237
237-244
244-251
251-258
258-265
265-272
272-279
470-478
478-486
486-494
494-502
502-510
510-518
518-526
526-534
534-542
542-550
550-558
558-566
566-574
574-582
582-590
590-598
598-606
606-614
614-622
622-630
630-638
638-646
646-654
654-662
662-670
670-678
678-686
686-694
694-702
702-710
710-718
718-726
726-734
734-742
742-750
750-758
758-766
766-774
774-782
782-790
790-798
798-806
806-814
814-822
822-830
830-838
838-846
846-854
854-862 |
Pix
48.25
55.25
62.25
119.25
126.25
133.25
140.25
147.25
154.25
161.25
168.25
175.25
182.25
189.25
196.25
203.25
210.25
217.25
224.25
231.25
238.25
245.25
252.25
259.25
266.25
273.25
471.25
479.25
487.25
495.25
503.25
511.25
519.25
527.25
535.25
543.25
551.25
559.25
567.25
575.25
583.25
591.25
599.25
607.25
615.25
623.25
631.25
639.25
647.25
655.25
663.25
671.25
679.25
687.25
695.25
703.25
711.25
719.25
727.25
735.25
743.25
751.25
759.25
767.25
775.25
783.25
791.25
799.25
807.25
815.25
823.25
831.25
839.25
847.25
855.25 |
Color
52.68
59.68
66.68
123.68
130.68
137.68
144.68
151.68
158.68
165.68
172.68
179.68
186.68
193.68
200.68
207.68
214.68
221.68
228.68
235.68
242.68
249.68
256.68
263.68
270.68
277.68
475.68
483.68
491.68
499.68
507.68
515.68
523.68
531.68
539.68
547.68
555.68
563.68
571.68
579.68
587.68
595.68
603.68
611.68
619.68
627.68
635.68
643.68
651.68
659.68
667.68
675.68
683.68
691.68
699.68
707.68
715.68
723.68
731.68
739.68
747.68
755.68
763.68
771.68
779.68
787.68
795.68
803.68
811.68
819.68
827.68
835.68
843.68
851.68
859.68 |
Sound
53.75
60.75
67.75
124.75
131.75
138.75
145.75
152.75
159.75
166.75
173.75
180.75
187.75
194.75
201.75
208.75
215.75
222.75
229.75
236.75
243.75
250.75
257.75
264.75
271.75
278.75
476.75
484.75
492.75
500.75
508.75
516.75
524.75
532.75
540.75
548.75
556.75
564.75
572.75
580.75
588.75
596.75
604.75
612.75
620.75
628.75
636.75
644.75
652.75
660.75
668.75
676.75
684.75
692.75
700.75
708.75
716.75
724.75
732.75
740.75
748.75
756.75
764.75
772.75
780.75
788.75
796.75
804.75
812.75
820.75
828.75
836.75
844.75
852.75
860.75 |
|
|
Chan
J-1
J-2
J-3
J-4
J-5
J-6
J-7
J-8
J-9
J-10
J-11
J-12
J-45
J-46
J-47
J-48
J-49
J-50
J-51
J-52
J-53
J-54
J-55
J-56
J-57
J-58
J-59
J-60
J-61
J-62 |
Pix
91.25
97.25
103.25
171.25
177.25
183.25
189.25
193.25
199.25
205.25
211.25
217.25
663.25
669.25
675.25
681.25
687.25
693.25
699.25
705.25
711.25
717.25
723.25
729.25
735.25
741.25
747.25
753.25
759.25
765.25 |
Sound
95.75
101.75
107.75
175.75
181.75
187.75
193.75
197.75
203.75
209.75
215.75
221.75
667.75
673.75
679.75
685.75
691.75
697.75
703.75
709.75
715.75
721.75
727.75
733.75
739.75
745.75
751.75
757.75
763.75
769.75 |
French
Chan |
Pix |
Sound |
F-2
F-4
F-5
F-6
F-7
F-8A
F-8
F-9
F-10
F-11
F-12 |
52.40
65.55
164.00
173.40
177.15
185.25
186.55
190.30
199.70
203.45
212.85 |
41.25
54.40
175.15
162.25
188.30
174.10
175.40
201.45
188.55
214.60
201.70 |
French
Chan |
Overseas
Pix |
Sound |
F-4
F-5
F-6
F-7
F-8
F-9 |
175.25
183.25
191.25
199.25
207.25
215.25 |
161.75
180.75
197.75
205.75
213.75
221.75 |
British
Chan |
Pix |
Sound |
B-1
B-2
B-3
B-4
B-5
B-6
B-7
B-8
B-9
B-10
B-11
B-12
B-13
B-14 |
45.00
51.75
56.75
61.75
66.75
179.75
184.75
189.75
194.75
199.75
204.75
209.75
214.75
219.75 |
41.50
48.25
53.25
58.25
63.25
176.25
181.25
186.25
191.25
196.25
201.25
206.25
211.25
216.25 |
|
|
Chan
4
5
6
7
8
9
10
11
13
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68 |
BW(MHz)
174-182
182-190
190-198
198-206
206-214
214-222
222-230
230-238
246-254
470-478
478-486
486-494
494-502
502-510
510-518
518-526
526-534
534-542
542-550
550-558
558-566
566-574
574-582
582-590
590-598
598-606
614-622
622-630
630-638
638-646
646-654
654-662
662-670
670-678
678-686
686-694
694-702
702-710
710-718
718-726
726-734
734-742
742-750
750-758
758-766
766-774
774-782
782-790
790-798
798-806
806-814
814-822
822-830
830-838
838-846
846-854 |
Pix
175.25
193.25
191.25
199.25
207.25
215.25
223.25
231.25
247.43
471.25
479.25
487.25
495.25
503.25
511.25
519.25
527.25
535.25
543.25
551.25
559.25
567.25
575.25
583.25
591.25
599.25
615.25
623.25
631.25
639.25
647.25
655.25
663.25
671.25
679.25
687.25
695.25
703.25
711.25
719.25
727.25
735.25
743.25
751.25
759.25
767.25
775.25
783.25
791.25
799.25
807.25
815.25
823.25
831.25
839.25
847.25 |
Sound
181.25
198.25
197.25
205.25
213.25
221.25
229.25
237.25
253.43
477.25
485.25
493.25
501.25
509.25
517.25
525.25
533.25
541.25
549.25
557.25
565.25
573.25
581.25
589.25
597.25
605.25
621.25
629.25
637.25
645.25
653.25
661.25
669.25
677.25
685.25
693.25
701.25
709.25
717.25
725.25
733.25
741.25
749.25
757.25
765.25
773.25
781.25
789.25
797.25
805.25
813.25
821.25
829.25
837.25
845.25
853.25 |
Eastern
Chan |
European
Pix |
Sound |
|
OIRT-1
OIRT-2
OIRT-3
OIRT-4
OIRT-5
OIRT-6
OIRT-7
OIRT-8
OIRT-9
OIRT-10
OIRT-11
OIRT-12 |
49.75
59.25
77.25
85.25
93.25
175.25
183.25
191.25
199.25
207.25
215.25
223.25 |
56.25
65.75
83.75
91.75
99.75
181.75
189.75
197.75
205.75
213.75
221.75
229.75 |
|
|
SIGNAL-TO-NOISE RATIO CHART
Signal to noise ratio, noise figure and signal level are
interrelated as shown on the nomograph.
Anybody working in TV knows that snow (noise) can be seen
in a TV picture when antenna signals are low, one can also
see that snow increases gradually as the signal level is
decreased, and that it is a matter of personal judgment
when the snow is so bad as to render a picture unusable.
The industry some years ago got together and showed TV
pictures to a large group of average people asking them
to rate picture quality in the presence of noise.
Out of this study came the TASO (Television Allocation
Study Organization) report with the finding that a signal
to noise ratio of 34 dB means a fine picture to an average
viewer, a 28 dB ratio means a passable picture and so on.
The TASO study used a bandwidth of 6 MHz, some people now
favor a bandwidth of 4 MHz, (the difference is indicated
on the nomograph) however, this is of minor importance
to most users of the graph.
|
Adjacent Channels Any of two TV channels are considered
adjacent when their frequencies are next to each other in frequency or
channel number.
Amplifier A device that boosts the strength of a television signal.
Analog A method of signal transmission in which information is
relayed by continuously altering the wave form of the electromagnetic
current. Now used in AM radio or most voice telephone circuits. In telephone
transmission, the signal being transmitted voice, video or image is "analogous"
to the original signal.
Antenna A wireless system component that converts wired electrical
energy to wireless radio waves, and directs them through the air in some
pattern.
Antenna Array An antenna comprising a number of radiating elements,
generally similar, which are arranged and excited to obtain directional
radiation patterns.
Attenuation In general terms, a reduction in signal strength.
Automatic Frequency An arrangement whereby the frequency of an
oscillator is automatically maintained within specified limits.
Automatic Gain Control A circuit for automatically controlling
amplifier gain in order to maintain a constant output voltage with a varying
input voltage within a predetermined range of input-to-output variation.
A process by which gain is automatically adjusted as a function of input
or other specified parameter.
Axial Ratio The ratio of the axes of the polarization ellipse.
Backhaul Point-to-point video transmission from a remote site back
to a central site for further distribution.
Band A clearly defined range of radio frequencies dedicated to
a particular purpose.
Bandwidth The number of cycles per second (Hertz) expressing the
difference between the lower and upper limiting frequencies of a frequency
band; also, the width of a band of frequencies. The range of frequencies
within which the performance of the antenna, with respect to some characteristic,
conforms to a specified standard. Greater bandwidth generally provides
for a more robust system because changes in the installation environment
will not degrade antenna performance.
Bandwidth A range of frequencies on the electromagnetic spectrum.
Beam width In a plane containing the direction of the maximum of
a beam, the angle between the two directions in which the radiation intensity
is one half the maximum value of the beam.
Bi-directional Communications between two points where each point
both transmits and receives.
Bird Slang for communications satellite.
Bounce Sudden variations in picture presentation (brightness, size,
etc.,) independent of scene illumination.
Broadband A descriptive term for evolving digital technologies
that provide consumers a signal switched facility offering integrated
access to voice, high-speed data service, video-on-demand services and
interactive delivery services.
Broadband In television system use, a device having a bandpass
greater than the band of a single VHF television channel.
CATV Cable TV A service through which subscribers pay to have local
television stations and other programs brought into their homes from the
antenna via coaxial cable
C-Band The 3.7 - 4.2 GHz (Gigahertz) frequency band is used for
the distribution of programming by virtually all satellite/cable networks.
There are 22 C-Band satellites in operation over North America today.
They range in power from 5-11 watts per transponder, requiring receive
antennas of 5-12 feet in diameter. Beginning in 1992, the fleet was gradually
replaced with higher powered (10-17 watt) satellites. This allows the
average size of a C-Band installation to be reduced to 90 inches in diameter.
Channel A 6 MHz wide portion of the RF spectrum carrying TV video
and audio carriers.
Clarke Belt The name given in honor of Arthur C. Clarke, to the
orbit 22,300 miles directly above the equator where satellites can maintain
a stationary position in relation to the earth. Also called geostationary
orbit.
Coax Short for coaxial cable.
Coaxial Antenna An antenna comprised of an extension to the inner
conductor of a coaxial line and a radiating sleeve which in effect is
formed by folding back the outer conductor of the coaxial line.
Coaxial Cable A type of cable capable of transmitting a range of
frequencies with low signal loss. Commonly used for transmitting video
and audio in security systems.
Coaxial Cable A type of cable commonly used in cable (CATV) and
direct broadcast satellite (DBS) television systems. Composed of two concentric
conductors (an inner wire and a braided shield) separated by a dielectric
material. The whole thing is usually wrapped in another insulating layer
and an outer protective layer. Most coaxial cable used in CATV and DBS
applications has an impedance of 75 ohms. A coaxial cable has great capacity
to carry great quantities of information. It is typically used to carry
high-speed data and in CATV (multiplexed TV stations.)
Compression A term used to denote reducing the amount of bandwidth
needed to transmit video or audio, thus increasing the capacity of a satellite
transponder. The reduction in gain at one level of a picture signal with
respect to the gain at another level of the same signal.
Crosstalk An undesired signal from a different channel interfering
with the desired signal.
dB Decibels A technique for expressing voltage, power, gain, loss,
or frequency in logarithmic form against a reference. Typical references
include volts, Watts or Ohms. An analog unit of measure of signal strength,
volume or signal loss due to resistance as expressed in logarithmic form.
A measure of the power ratio of two signals. In system use, a measure
of the voltage ratio of two signals, provided they are measured across
a common impedance.
Hz. Decibels are calculated using the expression: dB = 10*log(x/y)
dBi A ratio of decibels to an isotropic antenna that is commonly
used to measure antenna gain. The greater the dBi value, the higher the
gain and, as such, the more acute the angle of coverage.
dBmV A signal measurement whereby 0 dBmV equals 1000 microvolts
across 75 ohms. A recommended signal level for a TV to receive is 10 dBmV.
DBS Direct Broadcast Satellite A high-powered satellite that transmits
or retransmits signals which are intended for direct reception by the
public. The signal is received by a small (typically 18-inch diameter)
dish mounted on the sides of homes or on other buildings. Signal content
is generally television programing.
Decibel A unit to measure the relative levels of current, voltage
or power. This is the scale used to measure the strength of a TV signal.
An increase of 3 dB indicates a doubling of power.
Demodulation The process for retrieving an information signal that
has been modulated onto a carrier.
Descrambler Set-top box. A device which corrects a signal (often
video) that has been intentionally distorted to prevent unauthorized viewing.
Used with satellite TV systems.
Digital A method of storing, converting and sending data in the
form of binary digits ( 0 or 1). In displays, the use of digits for direct
readout. In telecommunications, in the recording or in computing, digital
is the use of a binary code to represent information. Analog signals (like
voice or music) are encoded digitally by sampling the voice or music analog
signals many times a second and assigning a number to each sample. Recording
or transmitting information digitally has two major benefits. The signal
can be reproduced more precisely so digital transmission is much "cleaner"
than analog transmission. The second major benefit of digital is that
the electronic circuitry to handle digital is getting cheaper and more
powerful.
Digital Recording Technology that enables video images to be stored
on a hard drive or other digital storage medium rather than on an analog
medium such as a videotape.
Dipole A type of low gain antenna consisting of two (often internal)
elements.
Directional Antenna An antenna having the property of radiating
or receiving electromagnetic waves more effectively in some directions
than others.
Dish cover A cylindrical weather protection device.
Dish Size Refers to the diameter of the dish, or antenna, used
in satellite reception.
Dish Slang term for antenna.
Distortion The deviation of the received signal waveform from that
of the original transmitted waveform.
Distribution Amplifier A device that provides several isolated
outputs from one looping or bridging input, and has a sufficiently high
input impedance and input-to-output isolation to prevent loading of the
input source.
Diversity Antenna An intelligent system of two antennas that continually
senses incoming radio signals and automatically selects the antenna best
positioned to receive it.
Downlink To receive from a satellite also, the dish used for reception.
DSL Digital Subscriber Line A generic name for a family of evolving
digital services to be provided by local telephone companies to their
local subscribers. Such services go by different names and acronyms -
ADSL (Asymmetric Digital Subscriber Line), HDSL (High Bit Rate Digital
Subscriber line) and SDSL (Single Pair Symmetrical Services). Such services
propose to give the subscriber up to eight million bits per second one
way, downstream to the customer and somewhat fewer bits per second upstream
to the phone company.
DTH Direct-To-Home. A term referring to all home satellite platforms.
DVR Digital Video Recorders (same as PVR).
Dynamic Range The difference between the maximum acceptable signal
level and the minimum acceptable signal level.
Embedded Antenna Typically an antenna that is enclosed into a product's
housing or case, or one that is not readily discernible by a casual observer.
The antenna forms an integral, inseparable part of the product.
Encryption/ Decryption Encryption is the process of electronically
altering a video and/or audio from its original condition. Decryption
is the process of returning the video and/or audio to its original condition.
EPG Electronic Programming Guide.
F-connector The final piece of hardware on a cable designed for
CATV or DBS or other signal distribution applications. It is cylindrical
with a center pin sticking out, that plugs into the set-top box, cable
ready TV, satellite receiver, or VCR.
Feedhorn The part of the satellite system that collects and focuses
satellite signals reflected by the antenna.
Fiber Optics Fiber A shortened way of saying "fiber optic."
Fiber is made of very pure glass. Digital signals, in the form of modulated
light, travel on strands of fiber for long distances. The big advantage
that fiber has over copper is that it can carry far, far more information
over much, much longer distances.
Field of View The maximum angle of view that can be seen through
a lens or optical instrument.
Field One of the two equal but vertically separated parts into
which a television frame is divided in an interlaced system of scanning.
A period of 1/60 second separates each field start time.
Filter A circuit that selects the frequency of desired channels
through the use of band pass, low pass, and high pass filters remove certain
unwanted signals to make room for the insertion of a new modulated TV
channel
Frequency Response The range of band of frequencies to which a
unit of electronic equipment will offer essentially the same characteristics.
Frequency The number of times an electromagnetic wave goes through
a complete cycle in one second, measured in Hertz.
FSS Fixed Satellite Service.
Gain An increase in voltage or power, usually expressed in dB.
In a given direction, 4 pi times the ratio of the radiation intensity
in that direction to the net power accepted by the antenna from the connected
transmitter. A measure of amplification expressed in dB. Gain of an amplifier
is usually specified at the highest frequency of operation.
Ghost A spurious image resulting from an echo.
GHz Gigahertz; one trillion cycles per second (a measure of frequency).
Ground Plane A conducting or reflecting plane functioning to image
a radiating structure.
GSO Geosynchronous Orbit; satellites in geosynchronous orbit travel
around the earth in an area approximately 22,300 miles from the surface
at the same rate that the earth turns, therefore completing one revolution
every 24 hours.
Headend A cable TV systems control center where incoming signals
from satellites and other sources are put into the system. (Head End)
The originating point of a signal in cable TV systems. At the head end,
you'll often find large satellite receiving antennae. A central control
device required within some LAN systems to provide such centralized functions
as remodultaion, re-timing, message accountability, connection control,
diagnostic control, and access.
Headend Homerun Wire The Homerun Wire is most often a single wire
(usually an RG6 or RG59 coaxial cable) that runs from each apartment building's
meter room to each apartment and is designed to deliver television or
telephone services. Some of the modern day Homerun Wires are being used
to deliver all services, cable and satellite television, telephone and
fax and high-speed Internet connections.
High Definition Television Technology that significantly increases
the resolution of digital video signals offering vastly improved picture
quality over the current NTSC standard.
Hum Electrical disturbance at the power supply frequency or harmonics
thereof.
Hybrid Satellite A satellite that carries two or more different
communications payloads (i.e., C-Band and Ku-Band).
Hz Hertz Cycle per second; a measure of electromagnetic frequency
that represents the number of complete electrical waves in a second. One
kilohertz (kHz) is one thousand cycles per second; one megahertz (MHz)
is one million; one gigaHertz (GHz) is one billion.
Impedance (input or output) The input or output characteristic of a system
component that determines the type of transmission cable to be used. The
cable used must have the same characteristic impedance as the component.
Expressed in ohms. Video distribution has standardized on 75-ohm coaxial
and 124-ohm balanced cable.
Impulse Pay-Per-View Technology that allows the consumer to purchase
a movie or special event instantly via a computerized order processing
center. This technology allows for the processing of a high volume of
orders in a short time period.
Input Impedance The impedance presented by an antenna at its terminals.
Inside Wiring That wiring located inside your premises or building.
Inside wiring starts at the telephone or cable company's Demarcation Point
and extends to the individual extensions. Traditionally, Inside Wiring
was installed and owned by the installing company.
Interference Extraneous energy which tends to interfere with the
reception of the desired signals.
IPG Interactive Programming Guide.
IRD(integrated receiver decoder) A device capable of receiving
and tuning satellite signals. The output of the receiver can be either
Baseband video for use with video monitors or RF for use with standard
TV sets.
Isolation Amplifier An amplifier with input circuitry and output
circuitry designed to eliminate the effects of changes made at either
upon the other.
Isolation Between Antennas A measure of power transfer from one
antenna to another - the ratio of power input to one antenna to the power
received by the other, usually expressed in decibels.
Isotropic A hypothetical antenna having equal radiation intensity
in all directions.
Jitter Small, rapid variations in a waveform due to mechanical
disturbances or to changes in the characteristic of components. Supply
voltages, imperfect synchronizing signals, circuits, etc.
kA-Band A higher frequency than Ku-Band, operating from 18 to 31
gigaHertz.
kHz Kilohertz.
Ku-Band The 11.7-12.7 GHz (Gigahertz) frequency band. This band
has been split into 2 segments by the FCC. The first is the 11.7-12.2
GHz band known as FSS (Fixed Satellite Service) There are 22 FSS
Ku-Band satellites in orbit over North America today. They range in power
from 20-45 watts per transponder, requiring a 3-5 foot antenna for clear
reception. The 12.2 - 12.7 GHz segment is known as BSS (Broadcast Satellite
Service). Satellites in this band range in power from 100 - 200 watts
per transponder, allowing the use of receive antennas as small as 12-18
inches.
L-Band Potion of electromagnetic spectrum commonly used in satellite
and microwave applications with frequencies in the 390 MHz to 1550 MHz
range. The GPS (global positioning system) frequencies are in the
L-Band. GPS uses 1227.6 MHz and 1575.42 MHz
LEO Low Earth Orbit; satellites placed in orbit less than 22,300
miles above the earth.
Light Electromagnetic radiation detectable by the eye, ranging
in wavelength from about 400 to 750 nm.
Line Amplifier An amplifier for audio or video signals that feeds
a transmission line; also called program amplifier.
Line of Sight An unobstructed straight line between two transmitting
devices. Line of sight is typically required for long-range directional
radio transmission. Due to the curvature of the earth, the line of sight
for devices not mounted on towers is limited to 16 miles (26 km).
LNB Low Noise Block convertor. System devise used to amplify and
convert satellite signals into frequencies sent to the tuner.
Loop Through Also called looping. The method of feeding a series
of high impedance circuits (such as multiple monitor/displays in parallel)
from a pulse or video source with a coax transmission line in such a manner
that the line is bridged (with minimum length stubs) and that the last
unit properly terminates the line in its characteristic impedance. This
minimizes discontinuities or reflections on the transmission line.
Loss A reduction in signal level or strength, usually expressed
in dB. Power dissipation serving no useful purpose.
Low-Frequency Distortion Distortion effects which occur at low
frequencies. In television, generally considered as any frequency below
the 15.75 kHz line frequency.
Matrix Switcher A device that routes any of its inputs to any of
its outputs. Inputs are normally cameras or alarms, and outputs are normally
recorders or monitors. A matrix switcher allows a user to control what
information is sent where within a large security network.
MHz Megahertz, a measure of frequency in millions (mega) of cycles
per second.
MMDS Multipoint Multi-channel Distribution Service. MMDS is a way
of distributing cable television signals, through microwave, from a single
transmission point to multiple receiving points. Often used as an alternative
to cable-bases cable TV. An MMDS service, "in digital form, will
provide more than 100 channels to a radius of approximately 40 miles from
the transmitter. The MMDS transmitter delivers video to homes that are
in its 'line of sight.' MMDS transmissions are limited by the terrain
and foliage of a given market. The microwave signal is received by an
antenna on the subscriber's home, then sent down coaxial cable to a box
atop the customer's TV set. The box decodes and decompresses the digital
signal." MMDS is increasingly being called "Wireless Cable."
Modems Acronym for Modulator/Demodulator. Conventional modems comprise
equipment which converts digital signals to analog signals and vice versa.
Conventional PC modems outputs data in the form of "1's" and
"0's" which are represented by varying levels of voltage. The
modem converts the digital data signal into variations of the analog sine
wave so the data can be transmitted over the device with a digital bit
stream. The modulation techniques include some combination of Amplitude
Modulation (AM), Frequency Modulation (FM) and Phase Modulation (PM),
also known as Phase Shift Keying (PSK). Used in combination, these techniques
allow multiple bits to be represented with a single (or single set) OF
SINE WAVES). In this fashion, compression is accomplished, which allows
more data to be transmitted in the same period of time and which therefore
reduces the connect time and the associated cost of the data transfer.
Modulation The process of superimposing an information signal onto
a carrier for transmission. The process where some characteristic of one
signal is varied in accordance with another signal. The carrier may be
modulated in three fundamental ways: by varying the amplitude, called
amplitude modulation; by varying the frequency, called frequency modulation;
by varying the phase, called phase modulation. The creation of a TV channel
from a video and audio source for transmission over a distribution coaxial
cable network.
Modulator The electronic equipment required to combine video and
audio signals and convert them to TV radio frequencies (RF) for distribution
to other equipment (including televisions) on a cable network.
MPEG Motion Pictures Experts Group.
Multiplexer A device that can accept a number of camera inputs
and almost simultaneously display them on a single monitor. Can be used
to transmit multiple cameras over the same transmission medium. A device
that accepts video signals from more than one camera and encodes them
onto one signal that is sent to a digital recorder or VCR. The multiplexer
also decodes the recording so it can play back video from one camera or
several cameras at once on a monitor.
NAB National Association of Broadcasters.
NCTA National Cable Television Association.
Noise The word "noise" originated in audio practice and
refers to random spurts of electrical energy or interference. In some
cases, it will produce a "salt-and-pepper" pattern over the
televised picture. Heavy noise is sometimes referred to as "snow".
NTSC Abbreviation for National Television Systems Committee. A
committee that worked with the FCC in formulating standards for the present
day United States color television system. A television industry group
that develops standards for standard television broadcasting and receiving
equipment in the US.
Off-Air Reception of a TV signal that has been broadcast through
the air by a TV station.
Omni-directional Antenna An antenna having an essentially non-directional
pattern in azimuth, and a directional pattern in elevation.
Output The signal level at the output of an amplifier or other
device.
Packet Data A process where stored data is transmitted in discrete units,
called packets, allowing for more efficient use of channel capacity and
reliability of transfer.
Patch Cords Cables used to interconnect electronic equipment often
terminated with modular or RCA-type plugs.
Patch Panel A panel where circuits are terminated and facilities
provided for interconnecting between circuits by means of jacks and plugs.
PCS Personal Communications System.
Peak Pulse Amplitude The maximum absolute peak value of a pulse,
excluding those portions considered to be unwanted, such as spikes.
Peak-to-Peak The amplitude (voltage) difference between the most
positive and the most negative excursions (peaks) of an electrical signal.
A full video signal measures one volt peak to peak.
Personal Video Recorder (PVR) Product that tracks viewing habits,
records programs and has other interactive features such as pause and
rewind.
PIFA Planer Inverted F Antenna.
Polarization In a given direction, the polarization of the wave
radiated by the antenna. Alternatively, the polarization of a plane wave
incident from the given direction which results in maximum available power
at the antenna terminals.
PVR Personal Video Recorder. A consumer device which uses a hard
disk drive to record television programs based on the user's preferences.
QPSK Quaternary Phase Shift Keying; a digital modulation scheme
used in transmission communications that allows increased sending capacity
Radiation Pattern (antenna pattern) A graphical representation
of the radiation properties of the antenna as a function of space coordinates.
Radome An enclosure for protecting an antenna from the harmful
effects of its physical environment, generally intended to leave the electrical
performance of the antenna unaffected.
Resolution (horizontal) The amount of resolvable detail in the
horizontal direction in a picture. It is usually expressed as the number
of distinct vertical lines, alternately black and white, which can be
seen in a distance equal to picture height.
RF Radio Frequency The area (or band) of the electromagnetic spectrum
where most radio communication takes place, typically from 100 KHz to
100 GHz. A frequency at which coherent electromagnetic radiation of energy
is useful for communication purposes. Analog electrical signals sent on
cable or over the air. Conventional (broadcast) television and radio,
as well as cable TV, deliver RF signals to your television/radio.
Ripple Amplitude variations in the output voltage of a power supply
caused by insufficient filtering.
Satellite Antenna (Dish) A parabolic antenna that collects satellite
signals. C-Band antennas range in size from 5-12 feet in diameter; K-Band
antennas range from 18 inches to 6 feet.
Satellite Programmer A company that produces, packages or distributes
video, audio, and/or data services for distribution to the home satellite
dish and cable markets.
SCPC Single Channel Per-Carrier; an economical way to get multiple
signals on one transponder.
Scrambling Altering a video signal transmission so it can not be
received without an authorized operating decoder.
Signal Leakage (Leakage) is a cable TV term. Leakage occurs when
certain radio frequencies ooze out of the CATV's coaxial cable in such
strength that they are evident outside the home. They might be sufficiently
strong to interfere with aircraft navigation. Leakage is really a shielding
problem.
Smart Card Technology that allows for the upgrade of encryption
security through the use of a consumer-installable card containing a new
computerized security code.
SMATV Dish & DBS Dish The dish-like antenna used to receive
satellite signals.
SMATV Satellite Master Antenna Television; or private cable; a
miniature cable system that receives programming by one satellite dish
and serves an entire housing complex, hotel or apartment etc.
Splitter A passive device (one with no active electronic components)
which distributes a television signal carried on a cable in two or more
paths and sends it to a number of receivers simultaneously.
Spread Spectrum A means of transmission in which encoded information
is carried in discrete packages of information, then spread over a wide
bandwidth for transmission to specific receivers that filter out the coded
material.
Stubby Antenna A short thick monopole.
Sun Outage When the sun passes behind a satellite in relation to
the earth and it‰s energy momentarily interferes with the satellite
signals. This happens two times each year during spring and fall equinox.
Superstation A local TV station whose signal is satellite delivered
to cable systems and backyard antennas across the country.
Switcher A simplified SEG that selects and mixes video signals
from two or more sources.
TDMA Time Division Multiple Access is one of several technologies
used in digital wireless transmissions that increases the efficiency of
the network by allowing a greater number of simultaneous transmissions.
Networks using TDMA assign 6 time slots for each frequency channel. Devices
using the wireless network send bursts of information that are reassembled
at the receiving end.
Terrestrial In communications parlance, this refers to earth, land or
ground-based telecommunications systems.
TNC (RP-TNC) A connector type unique to Net WORLD radios and antennas.
Part 15.203 of the FCC rules covering spread-spectrum devices limits the
types of antennas that may be used with transmission equipment. In compliance
with this rule, Net WORLD, like all other wireless LAN providers, equips
its radios and antennas with a unique connector to prevent attachment
of non-approved antennas to radios.
Transceiver A combination transmitter and receiver.
Transients Signals which exist for a brief period of time prior
to the attainment of a steady-state condition. These may include overshoots,
damped sinusoidal waves, etc.
Transponder A satellite component that receives and retransmits
a TV signal or perhaps many narrower-band data or audio channels.
TVRO (Television Receive-Only) An industry term used to describe
a home satellite system that only receives and does not transmit satellite
television signals.
UHF Ultra High Frequency The part of the radio spectrum from 470
MHz to 806 MHz, including TV channels 14 through 83.
Uplink To transmit to a satellite for relay; also, the dish used
to transmit.
Vertical Resolution The number of horizontal lines that can be
seen in the reproduced image of a television pattern.
VHF Very High Frequency. The part of the radio spectrum from 54
to 88 MHz and 174 to 216 MHz, which includes TV channels 2 through 13.
Video Amplifier A wideband amplifier used for passing picture signals.
Video Band The frequency band width utilized to transmit a composite
video signal.
Video Signal (Non-Composite) The picture signal. A signal containing
visual information and horizontal and vertical blanking (see also Composite
Video Signal) but not sync.
Wireless Transmission A technology in which electronic devices
send information to receivers using radio waves rather than wiring.
Wireless A system without outside wires, for example cellular telephony
or satellite television.
Zapping Changing the channel by remote control during a program
to avoid a commercial.
Zipping Fast-forwarding through commercials when playing back a
program on a VCR.
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