Abstract: 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.

Abstract: A method and apparatus for testing mobile communication devices involve utilizing the device's frequency hopping capabilities to substantially reduce the time required to measure operational parameters of the device at a plurality of frequencies across the device's operational frequency band. Prior to conducting the multi-frequency test, a device tester defines a hopping list of test frequency channels and transmits the hopping list and command signals to the mobile communication device for testing a set of operational parameters of the device at all of the test frequencies. The mobile communication device then measures all of the parameters at all of the frequencies by repeatedly sequentially hopping through the test frequencies in accordance with the hopping list.

Abstract: Method and apparatus for non-invasive testing of digital communications systems. Amplitude measurements are made for multiple frequencies of a multi-frequency communication system, converted to the time domain. An adaptive filter output is matched to the time domain representation to characterize the channel. Impedance mismatches may be precisely located using this technique. An error signal representing a difference between a signal transmitted through the channel and a received signal is estimated and analyzed. The error signal is separated into components corresponding to contributions by wide band noise, residual phase modulation, and residual amplitude modulation. Identification and removal of narrow-band interferers may occur prior to this separation. Bit error rate and system margin computations employ a Monte Carlo simulation of the various error sources. This provides a well refined estimate of bit error rate and system margin.

Abstract: In an antenna coupler (100) for testing mobile telephones (10), simple structure, which has a low coupling attenuation, is provided in that the antenna coupler (100) has the following features: a printed circuit board (1), on the upper side of which there is formed by a strip transmission line technique at least one antenna element (7,8); and a receiving element for a mobile telephone (10) secured to the upper side of the printed circuit board (1).

Abstract: A method of determining noise in a CATV channel, wherein the CATV channel comprises a predetermined frequency band, that employs digital signal processing to isolate the noise signal from an in-service television signal. The method includes an initial step of obtaining a television signal corresponding to a predetermined CATV channel, the television channel comprising a carrier signal modulated by an information signal. Thereafter, the method includes the step of sampling at least a part of the television signal to produce a digital signal segment, said digital signal segment comprising a carrier component, a noise signals component, and an information signal component, wherein said information signal component has a substantially predetermined signal pattern. The method then employs digital signal processing to separate the carrier component from the digital signal segment to produce a baseband signal substantially comprising the information signal and the noise signal.

Abstract: A method, system and apparatus for frequency sweeping and frequency sweep testing a CATV system wherein the CATV system has a plurality of channels and is transmitting television signals over at least some of the channels. The system includes a head end test unit coupled to the CATV system at its head end and a remote test unit coupled to the CATV system at a location remote from the head end. The head end test unit sweeps the CATV system by either generating and transmitting test signals at the channel frequencies over the CATV system or, if a television signal is being transmitted on a channel, using the television signal as the test signal. The head end test also measures the signal levels of the test signal and at the end of the sweep, transmits telemetry signals, which include the frequencies to be swept and the measured signal levels, over the CATV system to the remote test unit using the same transmitter that it use to generate and transmit the test signals.

Abstract: 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.

Abstract: Method and apparatus for non-invasive testing of digital communications systems. Amplitude measurements are made for multiple frequencies of a multi-frequency communication system, converted to the time domain. An adaptive filter output is matched to the time domain representation to characterize the channel. Impedance mismatches may be precisely located using this technique. An error signal representing a difference between a signal transmitted through the channel and a received signal is estimated and analyzed. The error signal is separated into components corresponding to contributions by wide band noise, residual phase modulation, and residual amplitude modulation. Identification and removal of narrow-band interferers may occur prior to this separation. Bit error rate and system margin computations employ a Monte Carlo simulation of the various error sources. This provides a well refined estimate of bit error rate and system margin.

Abstract: 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.

Abstract: 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.

Abstract: An RF circuit for use as a front end for a combined leakage signal detector and signal level monitor includes a shared frequency conversion stage utilized for both leakage signals and signal level monitoring ("SLM") signals. One embodiment of the present invention includes an RF circuit comprising a first RF input, a second RF input, a frequency conversion circuit and a coupling device. The first RF input is operable to receive first signals to be monitored, the first signals being in a first frequency range. The second RF input is operable to receive leakage signals to be detected, the leakage signals also being in a first frequency range. The frequency conversion circuit is operable to convert signals in the first frequency range to signals in a second frequency range, the frequency conversion circuit operable to receive unconverted first signals and unconverted leakage signals and produce output signals therefrom.

Abstract: 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.

Abstract: A method, system and apparatus for frequency sweeping and frequency sweep testing a CATV system wherein the CATV system has a plurality of channels and is transmitting television signals over at least some of the channels. The system includes a head end test unit coupled to the CATV system at its head end and a remote test unit coupled to the CATV system at a location remote from the head end. The head end test unit sweeps the CATV system by either generating and transmitting test signals at the channel frequencies over the CATV system or, if a television signal is being transmitted on a channel, using the television signal as the test signal. The head end test also measures the signal levels of the test signals and at the end of the sweep, transmits telemetry signals, which include the frequencies to be swept and the measured signal levels, over the CATV system to the remote test unit using the same transmitter that it used to generate and transmit the test signals.

Abstract: A method, system and apparatus for frequency sweeping and frequency swap testing a CATV system wherein the CATV system has a plurality of channels and is transmitting television signals over at least some of the channels. The system includes a head end test unit coupled to the CATV system at its head end and a remote test unit coupled to the CATV system at a location remote from the head end. The head end test unit sweeps the CATV system by either generating and transmitting test signals at the channel frequencies over the CATV system or, if a television signal is being transmitted on a channel, using the television signal as the test signal. The head end test unit also measures the signal levels of the test signals and at the end of the sweep, transmits telemetry signals, which include the frequencies to be swept and the measured signal levels, over the CATV system to the remote test unit using the same transmitter that it used to generate and transmit the test signals.

Abstract: A radio frequency ("RF") power sensor providing RF signal power sensing with reduced dependency upon its input signal power level includes multiple series-connected diodes for detecting the power of an input RF signal and providing an output voltage representing that power. The multiple series-connected diodes couple the input node shunted by an input load resistor to the output node shunted by an output filter capacitor. Using multiple series-connected diodes results in reduced reverse bias voltages across the diodes (presented by the charged output filter capacitor), thereby increasing their junction capacitances. These increased junction capacitances, in turn, result in reduced fractional changes thereof (e.g. capacitance "modulation") over changes in the input RF signal power. This reduction in fractional capacitance changes as a function of input signal power variations, further in turn, results in reduced input signal power dependency of the sensors' impedances and sensitivities.

Abstract: A peak-valley detector of an analog signal which provides a digital output of the analog signal. A digital counter is used having an output coupled to a digital-to-analog convertor. The output of the digital-to-analog convertor is compared to an input analog signal. The output of the comparator is used to control the input of a clock signal to the counter. A selective invertor controls whether the comparator's output allows counting for signals above or below the digital-to-analog convertor's output level.

Abstract: A swept microwave power measurement system and method capable of performing accurate high performance absolute power measurements on the fly for integration with a scalar analyzer. The system interpolates a calibration factor of the detector at a given frequency point in the sweep between previously established calibration factors at various predetermined frequencies which are stored in memory and then determines an "apparent" power level of the input signal at a standard frequency. The interpolated calibration factor is applied to the "apparent" power level to determine the "absolute" power level at the given frequency point in the sweep.