Intermediate frequency

The 10.7 and 455 kHz IF frequencies are more "historic" choices for superheterodyne receivers. The choices for these frequencies might have to do with availability of components (filters etc.) and/or frequency of the LO signal.

To receive for example a 100 MHz FM station, when IF = 10.7 MHz the LO can be either 89.3 MHz or 110.7 MHz. If an IF of 1 MHz was chosen then the LO frequency would need to be much closer to the frequency you want to receive introducing all kinds of problems.

The main problem is that the LO signal can find its way back into the receiver (LO feedthrough) so the radio would be receiving its own LO oscillator. Also the signal you want to receive should have a bandwidth of less than the IF frequency. For an FM receiver a 1 MHz IF would affect sound quality as it cannot properly handle the a 1 MHz frequency deviation of the FM signal.

Yes but then when IF = 0 Hz the LO is at the same frequency as the signal you want to receive !

Yes that is correct ! But in more modern receivers which are mainly implemented on a chip, not using discrete components, the issues caused by the LO being at the same frequency as the RX signal can be solved using a more complex architecture (Quadrature LO, LO supressing mixers, digital DC calibration etc.)

Modern receivers like for DAB and the ones in your (smart)phone are almost without exception Zero-IF or same thing, different name: Direct conversion receivers. See this lecture for more information.

These type of receivers are easier to implement on-chip. The issues like DC-offset and LO suppression can be handled by calibration and digital signal processing.

There are also (on-chip) AM and FM receivers using zero-IF so that superheterodyne architecture with 10.7 MHz IF is not strictly needed. But in "classical" designs there was less choice to do things differently.