General Instrument Corporation

Motorola Corporation

William C Hart, Jr

Robert G Uskali

Patrick D Smith

David J Smentek

John L Moran, Iii

Brian Creed

Brian Iehl

A method and an apparatus are employed for individually monitoring the connectivity status of cables connected at a cable modem termination system (CMTS), where the cables conduct upstream and downstream RF communication signals. The monitoring is self-contained within the CMTS. The monitoring is achieved by producing a reference signal having a frequency outside the frequency range of the RF communication signals. The reference signal is injected onto the RF communication signal. The power level of the reference signal is detected within the CMTS, whereby the power level correlates with an expected cable load impedance. A DC control voltage based on the detected power level of the reference signal is generated, which allows a controller to determine the connectivity statuses of the connected cables.

Non-intrusive cable connection monitoring for use in HFC networks

In a channelized system having a plurality of channels, an input spectrum having a plurality of signals is received by a receiver ( ). A first attenuation value (V ) is applied to a first variable gain device ( ) and a second attenuation value (V ) is applied to a second variable gain device ( ), wherein the first variable gain device ( ) and the second variable gain device ( ) are within a common signal path. The receiver ( ) is tuned to a desired channel and a first power level is measured within the desired channel. The receiver ( ) is selectively tuned to at least one additional channel and a second power level within the at least one additional channel is measured, independent of the first power level. Based on measuring the power levels, a first modified attenuation value is applied to the first variable gain device ( ) and a second modified attenuation value is applied to the second variable gain device ( ).

Method and apparatus for obtaining optimal performance in a receiver

A loop filter and amplifier ( ) is configured to generate a control voltage (V ) by applying low gain to a correction voltage (V ) in response to an input signal (V ) indicating that the VCO ( ) is to operate at low frequencies and applying high gain to the correction voltage in response to the input signal indicating that the VCO is to operate at high frequencies. A loop filter and amplifier ( ) is configured to generate a control voltage (V ) by shifting the control voltage by an amount determined by an offset voltage (V ) and by adjusting the control voltage with a correction voltage (V ). An operational amplifier ( ) is configured to generate a difference between the amount determined by the offset voltage and the correction voltage.

Loop filter and amplifier for improved phase margin and decreased phase noise with VCOs

The present invention is a method and system for extracting information from a received signal with minimal loss due to noise. The system comprises of a transformer, for correlating the received signal to a wavelet function and producing wavelet decomposition coefficients, and a threshold circuit, which is responsive to the received signal, for applying predetermined threshold values based on the type of signal. Also included in the system is a filter, coupled to the transformer and threshold circuit, for altering the wavelet decomposition coefficients produced by the transformer using threshold values applied by the threshold circuit to produce altered wavelet coefficients from which the received signal is reconstructed with reduced noise.

Adaptive threshold algorithm for real-time wavelet de-noising applications

A direct down conversion receiver includes a signal filter having a selectable frequency response for receiving an input signal. The filtered signal is amplified by a variable gain amplifier, and the amplified signal is received as input by an analog-to-digital converter. The analog-to-digital converter generates a series of digital samples representative of the filtered signal. A controller measures a corresponding peaking ratio of the filtered signal from the series of digital samples for each of a plurality of frequency bands and selects the frequency response of the signal filter as a function of the measured peaking ratios. The signal filter may include an adjustable highpass filter and an adjustable lowpass filter. The cutoff frequency of the lowpass filter and the cutoff frequency of the highpass filter are selected to attenuate the level of the input signal in one or more of the plurality of frequency bands so that the signal presented to the analog-to-digital converter has a peaking ratio approximately equal to a selected peaking ratio threshold across the frequency range of the input signal.

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Huntley, IL, United States of America

William C Hart, Jr