Wavetek Corporation

Wavetek Wandel Goltermann

Douglas J Franchville

Andrew E Bowyer

Daniel Keith Chappell

An exemplary embodiment of the present invention is an apparatus for receiving sweep testing signals and generating frequency response values therefrom. The apparatus includes a test input, a controller, a receiver circuit and a measurement circuit. The test input has a first connection arrangement for connecting to a test output of the sweep transmitter and also has a second connection arrangement for connecting to a terminal of the communication system to be tested. The controller is operable to generate a sweep control signal responsive to a sweep plan. The receiver circuit has a control input connected to receive the sweep control signal from the controller, and is operable to tune to a plurality of frequencies responsive to the sweep control signal. The measurement circuit is coupled to the receiver circuit and is operable to generate measurement signals corresponding to the plurality of frequencies. In accordance with the present invention, the controller is further operable to: receive a first set of measurement signals from the measurement circuit when said test input is connected in the first connection arrangement; receive a second set of measurement signals from the measurement circuit when said test input is connected in the second connection arrangement; and generate a frequency response based on the first set of measurement signals and the second set of measurement signals.

Preconfigured CATV sweep testing method and apparatus

An exemplary leakage tagging signal generator according to the present invention is intended for use in connection with a leakage tagging signal detector that detects signal leakage in a communication system. In particular, the leakage tagging signal generator is intended for use with a leakage tagging signal detector that identifies leakage tagging signals based on the detection of a characteristic leakage tagging frequency component. The leakage tagging signal generator includes an RF signal source, an output, a switch, and a pulse signal source. The RF signal source is operable to generate an RF carrier signal having a first frequency. The output connects to the communication system. The pulse signal source is a device operable to generate a pulse signal having a first state and a second state, said pulse signal having a pulse period. The pulse period of the pulse signal includes a first portion in which the pulse signal is in the first state and a second portion in which the pulse signal is in the second state. The pulse period futhermore corresponds to the characteristic tagging frequency. The switch is connected to the pulse signal source. The switch is operable to provide a first discrete signal level of the RF carrier signal to the output responsive to the pulse signal being in the first state, and to provide a second discrete level of the RF carrier signal to the output responsive to the pulse signal being in the second state, thereby producing a pulsed RF signal having the pulse period.

Method and apparatus for leakage detection using pulsed RF tagging signal

A signal power measurement apparatus for measuring the power of a first signal, with the first signal comprising a carrier signal modulated by an information signal. One embodiment of the present invention includes a signal power measurement apparatus comprising a RF receiver, an A/D converter, and a digital signal processing circuit. The RF receiver is operable to receive a first signal and generate an intermediate signal, with the intermediate signal comprising at least a portion of the first signal and having a bandwidth and a cutoff frequency. The A/D converter is operably connected to the RF receiver to receive the intermediate signal. The A/D converter generates a digital intermediate signal based on the intermediate signal, the digital intermediate signal having a sample rate less than twice the cutoff frequency. The digital signal processing circuit is operable to perform a power measurement on the digital intermediate signal, with the power measurement being representative of the power of at least a portion of the first signal.

Digitally modulated CATV power measurement using undersampling

Frequency domain reflectometer and method of locating faults in a transmission line utilized by the reflectometer are disclosed. The reflectometer suppresses harmonics that may be interpreted as faults that in actuality do not exist. In general, the reflectometer applies a sweep signal to the transmission line in order to obtain a reflected sweep response signal. Then, the reflectometer obtains a sweep response spectrum from the reflected sweep response signal. The reflected sweep response signal includes a plurality of spectral peaks which represent the frequency components of the reflected sweep response signal. Then, the reflectometer mathematically determines which spectral peaks of the reflected sweep response spectrum were generated due to harmonics in the reflected sweep response signal. After determining that a spectral peak is a harmonic of a fundamental spectral peak, the reflectometer subtracts a percentage of the fundamental spectral peak from the harmonic spectral peak, thereby suppressing a harmonic of the reflected sweep response signal. The reflectometer then obtains from the adjusted sweep response spectrum a location of an impedance mismatch in the transmission line.

Frequency domain reflectometer and method of suppressing harmonics

Frequency domain reflectometer and method of determining severity of faults in a transmission line are disclosed. The reflectometer compensates for attenuation effects in the transmission line when determining severity of faults. In general, the reflectometer applies a sweep signal to the transmission line in order to obtain a reflected sweep response signal. Then, the reflectometer obtains a sweep response spectrum from the reflected sweep response signal. The reflected sweep response signal includes a plurality of spectral peaks which represent the frequency components of the reflected sweep response signal. Then, the reflectometer determines a first attenuation compensation factor for a first spectral peak of the reflected sweep response spectrum. Furthermore, the reflectometer adjusts the reflected sweep response spectrum for effects due to attenuation in the transmission line by applying the attenuation compensation factor to the first spectral peak, thus compensating the reflected sweep response spectrum for attenuation within the transmission line. The reflectometer then obtains from the adjusted sweep response spectrum severity of an impedance mismatch in the transmission line.

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Indianapolis, IN, United States of America

Douglas J Franchville