If you are looking for a technique to transmit digital information over RF paths, first I suggest you educate yourself on how digital is transmitted via radio in the first place.
There are several techniques. I suggest you learn about Phase Shift Keying and Frequency Shift Keying. You should also learn about modems and digital signal processing.
The key here is MODEM. (Modulator/demodulator). To transmit digital over radio, the signal has to be modulated over an RF carrier. The frequency and bandwidth of the carrier must be high and broad enough to accomodate a modulation scheme with high bit rate transfer. Broadbanded transmissions are typically undesireable, so digital broadcasting at higher bit rates is typically done at at VHF or UHF or above where the higher frequency permits higher data throughput over a narrower signal. Slower speed data is also feasable at HF and some narrow mode voice techniques have been developed. Simple mono-voice can be efficiently replicated digitally with narrow bandwidth by sampling only the critical voice frequency range required for audibility. Lower end bass and high end treble can be elimated with L-C filtering, for instance.
Remember, you need a MODEM. A modem is a device that converts audio into digital, and vice versa. A computer soundcard can be used as a modem. The transmitted radio signal is actually high frequency shifts of audio frequency. The RF signal that the radio pics up is demodulated by the radio and the audio is fed to the computer soundcard, accomplished with an audio transformer typically to impedance match the microphone input to the radio. The signal processor in the sound card then converts the signal into digital format that the computer microprocessors and software can understand. This will then be converted back into analog audio, but now it will be recognizeable as a human voice or music or whatever through the computer speakers.
All of this can also be accomplished with special radio equipment with built in modems , microprocessors, and signal processors/soundcards. But it is much easier to just outfit a radio with a computer connection and utilize whats already there.
The computer needs software written to communicate with the soundcard and analyze the waveforms that the soundcard signal processor is recieving. The software must be able to convert the audio presented to it into a specific digital language and vice versa.
I suggest you get ahold of the current ARRL publication on digital communication techniques. If you would like to experiment with transmitting digital voice, there are plenty of amateur radio experimenters who can guide you and help you set up the equipment.