25:
258:. The intercarrier receiver system makes for easier tuning of a TV station. The viewer could fine tune such a set to get the best picture reception, and not lose sound reception. (Although AF VF signals are combined in the IF stages of the transmitters, they are separated in baseband stages of the receivers.)
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In TV receivers, the received radio frequency signal is converted to IF in tuner and then demodulated. The output of the demodulator consists of a VF and an aural signal which is in fact an FM subcarrier modulated by AF. (The subcarrier is 5.5 MHz in system B and 4.5 MHz in system M ) The
288:. However, out of band product means an unwanted transmission in the neighbour TV channels. For example, intermodulation products of channel 7 appear in channel 5,6, 8 and 9. That is why notch filters are used in intercarrier system.
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to suppress the intermodulation products is used at the output of the intercarrier transmitter, the cost of the notch filter is not comparable to the cost of extra amplifiers and the output combiner. (See the subsection
272:
When VF and the aural signal modulate the same carrier the inevitable non-linearity of the electronic circuits cause unwanted signals which are called intermodulation products. The unwanted signals appear on
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is a system in television that reduces the cost of transmitters and receiver sets by processing audio and video signals together and minimizing the number of separate stages for audio and video signals.
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is a very costly solution, because every stage must be used twice, one for AF and one for VF. Two separate transmitters, a high power combiner and a common antenna system, known as the
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or at the output of the vestigial sideband stage. In both cases, the added signals are low level signals and no special combining circuitry is required.
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are spared, which reduce the cost of the transmitter and electricity consumption of the amplifiers considerably. Although a
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In TV broadcasting the intermodulation products of the aural subcarrier and the main carrier appear out of the
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aural signal and the VF are separated by a simple filter. The only extra stage needed for AF (other than the
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at regular intervals, the interval being equal to the frequency difference of the visual and aural carriers.
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196:(IF) carriers. (The frequency difference between the two carriers is 4.5 MHz in
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222:(or a mixer) and a series of amplifiers for aural signal as well as an output
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This common signal processing system is known as the intercarrier system.
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204:) Then the modulated IF signals are added either at the output of the
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sets. If the modulated signal is separated just before the
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the number of separate stages for AF and VF is minimized.
307:, Glencoe, McGraw Hill, New York, 6th ed, 1999, p 469.
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49:. Unsourced material may be challenged and removed.
149:Transmitting those signals by means of separate
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8:
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262:Intermodulation products and notch filters
109:Learn how and when to remove this message
762:Output power of an analog TV transmitter
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179:Intercarrier as used in TV transmitters
130:Transmission of audio and video signals
792:Direct-broadcast satellite television
239:Intercarrier as used in receiver sets
7:
47:adding citations to reliable sources
682:Vestigial sideband modulation (VSB)
189:In TV transmitters, both AF and VF
305:Basic Television and Video Systems
14:
23:
677:Quadrature amplitude modulation
303:Bernard Grob,Charles E.Herndon:
164:The same logic also applies to
34:needs additional citations for
841:Television channel frequencies
1:
812:Digital television transition
641:Multichannel television sound
884:Field strength in free space
585:Horizontal blanking interval
782:Superheterodyne transmitter
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620:Vertical blanking interval
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242:
182:
595:Nominal analogue blanking
233:Intermodulation products
914:Television interference
787:Television receive-only
1012:Broadcast transmitters
836:Microwave transmission
802:Terrestrial television
797:Television transmitter
757:Intermediate frequency
550:Chrominance subcarrier
194:intermediate frequency
185:Television transmitter
1007:Broadcast engineering
1002:Television technology
708:Broadcast transmitter
58:"Intercarrier method"
950:Zero reference pulse
935:Field strength meter
672:Frequency modulation
580:Horizontal scan rate
212:Frequency conversion
200:and 5.5 MHz in
43:improve this article
889:Noise (electronics)
752:Intercarrier method
712:Transmitter station
347:broadcasting topics
220:frequency converter
123:intercarrier method
16:Broadcasting method
777:Split sound system
727:Differential phase
159:split sound system
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904:Radiation pattern
722:Differential gain
344:Analog television
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831:Frequency offset
772:Residual carrier
717:Cavity amplifier
615:Television lines
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218:is common. So a
206:vision modulator
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256:FM demodulator
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146:(VF) signals.
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625:White clipper
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468:Color systems
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216:amplification
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99:November 2009
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60: –
59:
55:
54:Find sources:
48:
44:
38:
37:
32:This article
30:
26:
21:
20:
976:Hanover bars
767:Pre-emphasis
751:
691:Transmission
656:Zweikanalton
560:Color killer
485:Clear-Vision
304:
299:
279:
271:
248:
232:
228:notch filter
210:
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174:
170:picture tube
163:
151:transmitters
148:
133:
122:
120:
105:
96:
86:
79:
72:
65:
53:
41:Please help
36:verification
33:
945:VIT signals
940:Vectorscope
879:Earth bulge
861:Propagation
824:& bands
822:Frequencies
605:Raster scan
545:Chrominance
535:Black level
530:front porch
275:RF spectrum
252:loudspeaker
996:Categories
874:Distortion
807:Transposer
742:Dummy load
698:Amplifiers
665:Modulation
555:Colorburst
526:Back porch
292:References
286:TV channel
202:System B/G
136:television
69:newspapers
981:Sparklies
966:Dot crawl
959:Artifacts
899:Path loss
894:Null fill
869:Beam tilt
610:Safe area
142:(AF) and
971:Ghosting
732:Diplexer
600:Overscan
565:Color TV
458:System F
454:System E
450:819-line
444:System N
440:System L
436:System K
432:System I
428:System H
424:System G
420:System D
416:System C
412:System B
408:625-line
402:System M
398:525-line
393:455-line
388:441-line
382:System A
378:405-line
373:375-line
368:343-line
363:180-line
254:) is an
224:combiner
198:System M
191:modulate
166:receiver
923:Testing
505:PALplus
355:Systems
284:of the
282:RF band
235:below)
83:scholar
480:NTSC-J
85:
78:
71:
64:
56:
646:NICAM
634:Sound
519:Video
510:SECAM
500:PAL-S
495:PAL-M
144:video
140:audio
90:JSTOR
76:books
909:Skew
590:Luma
528:and
475:NTSC
214:and
153:and
121:The
62:news
851:VHF
846:UHF
490:PAL
134:In
45:by
998::
456:,
442:,
438:,
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452:(
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410:(
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380:(
336:e
329:t
322:v
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106:(
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97:(
87:·
80:·
73:·
66:·
39:.
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