Patent ID: 6693917
Filing Date: 2004-02-17
Classification: H04L

Abstract:
An apparatus comprising:a media for carrying high speed digital data from a high speed digital data transmitter to a high speed digital data receiver; a subchannel transmitter having an output coupled to said media and having an input for receiving subchannel data which is separate from and at a much lower baud rate than said high speed digital data and including a modulator which modulates such subchannel data onto a host signal for propagation across said media; a subchannel receiver having an input coupled to said media through a means for passing the frequency components of the subchannel data spectrum but not passing the frequency components of the high speed data spectrum, and having an amplifier that amplifies the output of said low pass filter and having a mixer and local oscillator that combine to mix the frequencies output by said amplifier down to an intermediate frequency, and having a bandpass filter for filtering the intermediate frequency signal using a passband which is centered on said intermediate frequency and which has a bandwidth which is wide enough to encompass enough of the frequency components of the subchannel data spectrum and exclude enough of the frequency components of the high speed data signal to provide adequate sensitivity and selectivity of said subchannel receiver to detect said subchannel data signal despite manufacture lot variations in the rise times of said high speed data signals, and having one or more detectors to detect the subchannel data.