Methods and apparatus for baseband digital spectrum translation (bdst)

Abstract

A method for transmitting and receiving digitally modulated wireless signals using an analog FM transceiver is provided. The analog FM transceiver has a transmit speech audio frequency band, a receive speech audio frequency band substantially equal to the transmit speech audio frequency band, a subaudible frequency band, a direct microphone audio input, and a direct speaker audio output. The method includes generating, in a baseband digital spectrum translator external to the analog FM transceiver, a baseband transmit signal occupying frequencies substantially within the transmit speech audio frequency band of the analog FM transceiver. The method also includes applying the generated baseband transmit signal to the direct microphone audio input to thereby transmit a digitally encoded RF TX signal having a constant envelope and using the analog FM transceiver to receive a digitally encoded RF RX signal with a constant envelope and to generate a baseband receive signal using the digitally encoded RF RX signal. The method also includes generating, in the baseband digital spectrum translator, a speaker audio signal using the baseband receive signal.