The intercarrier method 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.
Transmitting those signals by means of separate transmitters and antenna systems is a very costly solution, because every stage must be used twice, one for AF and one for VF.
In TV transmitters, both AF and VF modulate intermediate frequency (IF) carriers.
The output of the demodulator consists of a VF and an aural signal which is in fact an FM subcarrier modulated by AF.
[1] The intercarrier receiver system makes for easier tuning of a TV station.