Without looking up what kind of encoding and modulation they are using, I would assume that they are sending a continuous sine wave at the carrier frequency tha

Without looking up what kind of encoding and modulation they are using, I would assume that they are sending a continuous sine wave at the carrier frequency that has the bits - probably after encoding the raw data bits with some error correction code - modulated onto it by changing frequency, amplitude, phase, or a combination of them depending on the value of each bit or group of bits.