Agilent Technologies, Inc.

Keysight Technologies, Inc.

Hewlett-packard Company

Robert Thomas Cutler

Andrew David Fernandez

Daniel Lee Pleasant

John C Eidson

Dietrich Werner Vook

Glenn R Engel

David Lee Gines

Gopalakrishnan Kailasam

Leon K Werenka

John E Neeley

Harry G Plate

Laurence Dale Bennett

Mutsuya Li

Deitrich Werner Vook

John B Stratton

An apparatus and method for measuring the properties of a DUT characterized by a signal gain applied to an input signal to that DUT and a DUT noise spectrum introduced by that DUT is disclosed. An apparatus includes first and second measurement channels and a controller. The first and second measurement channels are characterized by gains and noise spectrums that are different for the different channels and generate first and second measurement signals. The controller measures an average value of a product of the first and second measurement signals when an input signal is applied to the input of the DUT, the controller providing a measure of the signal to noise ratio of the output of the DUT, independent of the noise spectrums in the first and second measurement channels. Four channel embodiments reduce the amount of calibration needed to measure the gain and noise spectrum of the DUT.

Method and apparatus for estimating the noise introduced by a device

A method and system for determining a location of a first device that emits a signal: provide at least three sensors separated and spaced apart from each other; at each of the sensors, receive the signal emitted by the first device; determine the received signals for each of the sensors; determine cross-correlations of the received signals for pairs of the sensors; and determine the location of the first device from the magnitudes of the cross-correlations of the received signals.

Method and system for locating signal emitters using cross-correlation of received signal strengths

One or more of the programmable RF receivers or other devices in the network may be programmed to determine whether one or more defining characteristics associated with a particular RF transmitter or transmitter type are present in RF data. The one or more defining characteristics are used to detect the use of an RF transmitter or transmitter type.

Method and system for detecting an RF transmitter or transmitter type using a network of programmable RF receivers

A system and a method for displaying an emitter location are disclosed. The system includes a plurality of receivers at different locations in a field. Each receiver generates a receiver signal that depends on the magnitude of a signal from the emitter. The system also includes a processor that receives the receiver signal and generates a likelihood map indicative of an approximation of a probability as a function of position in the field of the emitter location. The likelihood map includes a plurality of receiver maps. Each receiver map includes a probability as a function of position in the field of the emitter location based on the signal magnitude for at least one of the receiver signals. Each receiver map may depend on a ratio of the signal magnitudes from a corresponding pair of the receivers, or on one of the signal magnitudes from a corresponding one of the receivers.

Likelihood map system for localizing an emitter

A number of RF receivers are connected in a network. The network is used to transmit communications, data, or both to and from the RF receivers and to synchronize the RF receivers to a common time. Digitized RF data is time-stamped and stored in memory. A trigger circuit in one or more RF receivers determines whether a trigger criterion or criteria has been met. When a trigger criterion or criteria has been met, some or all of the RF receivers in the network transmit select digitized RF data to a central processing device. The central processing device processes the select digitized data to detect if a signal is present.

Method and system for detecting an RF signal

A system and method are provided which coordinate the actions of a plurality of devices via scheduling occurrence of the actions based on synchronized local clocks of the devices. Thus, a plurality of devices are communicatively coupled via a communication network, and the devices have their local clocks synchronized to a high degree of precision, using IEEE 1588, NTP, or some other technique for synchronizing their local clocks. 'Time bombs' can be scheduled on the devices to coordinate the occurrence of actions between the devices in accordance with the detonation times set for the respective time bombs. In certain embodiments, not only the detonation time, but also the respective action to be triggered upon detonation is programmable for each device. The time bombs implemented on the various devices can be used to coordinate the operations of the various devices with a high degree of temporal precision.

System and method for coordinating the actions of a plurality of devices via scheduling the actions based on synchronized local clocks

Two or more receivers in a plurality of receivers are selected and the signal data from each receiver obtained. A cross-correlation of signal data is computed for each receiver paring in the selected receivers. The results of each cross-correlation are then combined and mapped into a graphical indicator function. The graphical indicator function generates a visual representation of location information using the results of each cross-correlation computation. The visual representation is then displayed to a user. Additional location information may also be simultaneously displayed with the visual representation or upon command.

Method and system for computing and displaying location information from cross-correlation data

A network of RF devices is connected to a central processing device and a common network clock. The central processing device and the RF devices exchange timing information in order to synchronize the network of RF devices to a common time defined by the common network clock.

Method and system for synchronizing a network of RF devices

A correction processor connected to an oscillator uses precision timing signals propagated over a digital network to generate an error signal. IEEE-1588 time synchronization protocols produce precision time signals which are converted to precision interval signals. The correction processor uses the precision interval signals to count pulses of the oscillator. A correction circuit compares the counter output with a predetermined value and generates an error signal may be used to correct the oscillator or may be propagated to consumers of the oscillator. An arbitrary reference oscillator may be used to generate the precision timing signals propagated on the network, to slave other oscillators to it. The precision of the reference oscillator may be deliberately overstated to insure it is used as a master.

Distributing frequency references

A system and method are provided which add, via an add-on module, synchronization functionality to an instrument that does not otherwise support such synchronization functionality. Various synchronization techniques may be supported by the synchronization module. For instance, in certain embodiments the synchronization module supports message-based synchronization techniques and/or time-based synchronization techniques. Accordingly, in certain embodiments, the add-on module supports synchronization with another device (e.g., another instrument or another add-on module coupled to an instrument) via synchronized local clocks (e.g., IEEE 1588) and messaging over a communication network. In certain embodiments, the add-on module additionally or alternatively supports the use of 'time bombs' to trigger scheduled actions on the instrument with which the synchronization module is interfaced.

Add-on module for synchronizing operations of a plurality of devices

Location of an emitter using leaky cables. A two-channel receiver determines the location of an emitter by measuring the phase and/or amplitude difference between emitter signals received by leaky cables. In one embodiment, two leaky cables having different propagation velocities are used. In a second embodiment also suitable for use with fiber optic cables, two cables having the same propagation velocity are used, but have different lengths, the extra length being taken up by serpentine patterns or loops. A single cable in a loop may also be used. The leak points on the cables may be passive, or may be controlled RF switches.

Locating energy sources using leaky conductors

In a response calibration method, a stimulus signal having a non-zero bandwidth is coupled to a receiver through a signal path that introduces distortion to the stimulus signal. The receiver acquires a first digital representation of the stimulus signal at an output of the signal path with the receiver adjusted to a first spectral position, and acquires a second digital representation of the stimulus signal at the output of the signal path with the receiver adjusted to a second spectral position that is shifted from the first spectral position by a predetermined frequency offset. The frequency response of the receiver when the receiver adjusted to the first spectral position is equated to the frequency response of the receiver when the receiver is adjusted to the second spectral position. A first combined frequency response of the receiver and the signal path is extracted at three or more designated frequencies within the bandwidth of the stimulus signal, and a second combined frequency response of the receiver and signal path is extracted at a set of frequencies offset from the three or more designated frequencies by the predetermined frequency offset. The frequency response of the receiver is determined from the first combined frequency response and the second combined frequency response. The frequency response of the signal path is optionally determined according to the response calibration method under condition that the stimulus signal is known, characterized, designated or otherwise established.

Response calibration method using a frequency-shifted receiver

The response of a receiver is calibrated using frequency-shifted stimulus signals. A source provides a stimulus signal that has a non-zero bandwidth and an adjustable spectral position. A signal path coupled between the source and the receiver introduces distortion to the stimulus signal. The receiver acquires a first digital representation of the stimulus signal at an output of the signal path with the stimulus signal adjusted to a first spectral position and acquires a second digital representation of the stimulus signal at the output of the signal path with the stimulus signal adjusted to a second spectral position that is shifted from the first spectral position by a predetermined frequency offset. A processor, designates the distortion introduced to the stimulus signal by the signal path to be equivalent at the first spectral position and the second spectral position. The processor extracts a first combined frequency response of the receiver and the signal path at three or more frequencies within the bandwidth of the stimulus signal, and extracts a second combined frequency response of the receiver and signal path at the three or more frequencies and then determines the frequency response of the receiver from the first combined frequency response and the second combined frequency response. The response of the signal path is optionally determined according to the response calibration scheme under condition that the stimulus signal is known, characterized, designated or otherwise established.

Response calibration scheme using frequency-shifted stimulus signals

Display of signals containing inter-symbol interference (ISI). An input signal is modeled as comprising an ideal signal plus ISI plus error. In a first embodiment of the invention, an error signal and an ideal signal are derived from the input signal. The ideal signal is combined with the error signal producing an ideal signal with errors. In a second embodiment of the invention, a first signal comprising the ideal signal plus ISI plus error is derived. A second signal comprising only ISI is derived, and subtracted from the first signal, producing a signal containing the ideal signal plus error.

Method of displaying signals in the presence of inter symbol interference

Power levels for a code-division multiple access (CDMA) signal with layered orthogonal codes are displayed. When displaying power levels for multiple code layers, a power level for each active code channel is displayed using a bar. A width of the bar indicates in which code layer each active code channel is active. A color of the bar also can be used to indicate in which code layer each active code channel is active. For example, a power level for each active code channel is displayed using a hollow bar and a power level for each inactive code channel is displayed using a line. Alternatively, a power level for each inactive code channel is displayed using a hollow bar and power level for each active code channel is displayed using a solid bar. When displaying a power level for a single code layer, a power level for each active code channel in the single code layer is displayed using a hollow bar, and a power level for each code channel which is inactive in the single code layer is displayed using a line. Alternatively, when displaying a power level for a single code layer, a power level for each active code channel in the single code layer is displayed using a solid bar, and a power level for each code channel which is inactive in the single code layer is displayed using a hollow bar.

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Everett, WA, United States of America

Robert Thomas Cutler