Simultaneous transmission of speech and data over an analog channel

A receiver comprising:

• an input terminal capable of simultaneously receiving an analog speech signal which includes a predetermined power density characteristic over a predetermined bandwidth and a data signal which is received in a portion of the received analog speech signal bandwidth where the analog speech signal is present and the power density characteristic of the analog speech signal is at a low value;
• a first and a second output terminal;
• means responsive to a received composite analog speech and modulated data signal at the input terminal for demodulating and recovering the data signal therefrom at an output thereof for transmission to the receiver first output terminal;
• means capable of remodulating the recovered data signal at the output of the demodulating and recovering means for generating an output signal corresponding substantially to the data signal received at the input terminal of the receiver;
• adaptive filtering means capable of generating a first signal representative of an estimate of an impulse response of a channel connected to the input terminal of the receiver, and convolving said first signal with the remodulated data output signal from the remodulating means to generate a resultant output data signal;
• and
• means capable of subtracting the resultant output data signal generated by the adaptive filtering means from the composite analog speech and data signal received at the input terminal of the receiver for substantially canceling the data signal forming part of the composite received signal and generating a resultant output signal at the second output terminal of the receiver which comprises the recovered analog speech signal.