Intercarrier method: Difference between revisions

Revision as of 23:39, 15 September 2010

Revision as of 05:22, 16 September 2010

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{{main|Intermodulation}}

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 [[RF spectrum]] at regular intervals, the interval being equal to the frequency difference of the twovisual mainand signalsaural carriers.

In TV broadcasting the intermodulation products of the aural subcarrier and the main carrier appear out of the [[Bandwidth (signal processing)|RF band]] of the [[TV channel]]. 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.