System for channel capacity modulation

A method of determining an optimum data rate for transmission of data over a transmission line, the method comprising the steps of:

• transmitting data signals having wideband characteristics from a first modem on the transmission line;
• obtaining the data signals in a second modem and, in response to the wideband characteristics of said data signals, a measure of the signal and noise spectrum present on the transmission line, the measure of the signal spectrum being obtained by a spectrum analyzer, and the measure of the noise spectrum being obtained by a signal-to-noise ratio circuit;
• transmitting from said second modem to said first modem data from both the spectrum analyzer and the signal-to-noise ratio circuit, the data from the spectrum analyzer being indicative of the measure of the signal spectrum present on the transmission line and the data from the signal-to-noise ratio circuit being indicative of the measure of the noise spectrum present on the transmission line;
• and
• optimizing in said first modem both bandwidth and data rate for the transmission line responsive to the measure of the signal and noise spectrum present on the line.

A system for transmission of data between first and second modems over a bandwidth constrained transmission line, the system comprising:

• means for transmitting data signals having wideband characteristics from said first modem on the transmission line;
• means for decoding the data signals in said second modem;
• means for decoding the data signals in said second modem;
• means for measuring in said second modem both the signal and noise spectrum present on the transmission line in response to receipt of the wideband characteristics of said data signals by both a spectrum analyzer and a signal-to-noise ratio circuit, the measure of the signal spectrum being obtained by the spectrum analyzer, and the measure of the noise spectrum being obtained by the signal-to-noise ratio circuit;
• means for transmitting from said second modem to said first modem data from both the spectrum analyzer and the signal-to-noise ratio circuit, the data from the spectrum analyzer being indicative of the measure of the signal spectrum present on the transmission line and the data from the signal-to-noise ratio circuit being indicative of the measure of the noise spectrum present on the transmission line;
• and
• means in said first modem for identifying both a maximum data rate and an optimum bandwidth for use by said first modem in the transmission of data over the transmission line in response to the signal and noise spectrum present on the transmission line.

A method of optimizing an analog modem for transmission of data over a bandwidth constrained transmission line, the method

• transmitting, in the analog modem, data signals having wideband characteristics on the transmission line;
• obtaining the data signals and, in response to the wideband characteristics of said data signals, a measure of the signal and noise present on the transmission line, the measure of the signal spectrum being obtained by a spectrum analyzer, and the measure of the noise spectrum being obtained by a signal-to-noise ratio circuit;
• transmitting to the analog modem data from both the spectrum analyzer and the signal-to-noise ratio circuit, the data from the spectrum analyzer being indicative of the measure of the signal spectrum present on the transmission line and the data from the signal-to-noise ratio circuit being indicative of the measure of the noise spectrum present on the transmission line;
• and
• identifying both a maximum data rate and an optimum bandwidth for use by the analog modem in the transmission of data over the transmission line in response to the measure of both the signal and noise spectrum present on the line.