초록 ▼

The present invention relates to a means for achieving simultaneous transmission of data and speech with only a minimal expansion of the bandwidth of the speech signal. A Fourier transform (14) is performed on the speech signal and a predetermined number of phase components are replaced with data (d

The present invention relates to a means for achieving simultaneous transmission of data and speech with only a minimal expansion of the bandwidth of the speech signal. A Fourier transform (14) is performed on the speech signal and a predetermined number of phase components are replaced with data (d(n)) in an appropriate form. The number of phase components replaced with data is determined by approximately classifying the speech (16) as either “silence”, no data inserted; “unvoiced”speech, M phase components convey data; and “voiced”speech, J phase components convey data; where J is less than M, and M is not greater than the number of phase components in the message band of the speech signal. An inverse Fourier transform (22) is subsequently performed on the combined data and speech signal. The combined message signal (G(t)) will comprise approximately the same bandwidth as the original speech signal, by virtue of the frequency domain insertion of the data into the speech. At the receiver the signal is inspected and a classifier (38) determines if data is embedded in the received signal. If data is deemed embedded, a Fourier transformation is performed, the data carrying phase components are inspected, and the data signal regenerated in an appropriate form. The phase components used for the conveyance of data are replaced by random phase components, and the inverse Fourier transformation performed. Median filtering is employed to mitigate the effects of end-of-block distortion and yield the recovered speech signal.

대표청구항 ▼

In a simultaneous transmission system for data and analog speech: a transmitter responsive to both an analog speech signal (s(t)) and a data stream (d(n)) for simultaneously transmitting the analog speech signal and the data stream as a combined message signal (G(t)) wherein the transmitter comprise

In a simultaneous transmission system for data and analog speech: a transmitter responsive to both an analog speech signal (s(t)) and a data stream (d(n)) for simultaneously transmitting the analog speech signal and the data stream as a combined message signal (G(t)) wherein the transmitter comprises combination means responsive to both said analog speech signal and said data stream for transforming said analog speech signal from a time domain representation into a frequency domain representation, inserting a predetermined portion of said data stream in an appropriate form in place of a selected portion of the frequency domain representation, and transforming said frequency domain representation into a time domain representation of the combined message signal output of the transmitter; and a receiver responsive to the combined message signal produced by said transmitter and recovering therefrom both said analog speech signal and said data stream wherein the receiver comprises separation means responsive to said combined message signal for transforming said combined message signal from a time domain representation into a frequency domain representation, removing and producing as a data output the predetermined portion of said data stream therefrom, inserting a plurality of random components in place of the removed portion of said frequency domain representation, and transforming said frequency domain into a time domain representation of a recovered analog speech signal.