Thanks, Cory - my understanding of these little marvels is greatly enhanced!
The radios don't have an IF. They are little software defined radios under the covers! They use the RDA1846 chip, which is a fully self-contained transceiver on a chip. They merely add a microcontroller to run the radio's functions, and receive and transmit amplifiers. The RDA1846 takes the receive input through a pair of mixers with a 90 degree phase shift on one to produce a quadrature output. This is fed into two ADC's, which feed the built in digital signal processor.