An interference cancellation device includes a data symbol extraction unit that extracts a data symbol portion from a received signal, a null symbol extraction unit that extracts a null symbol portion from the received signal, a data symbol power calculation unit that calculates a data symbol power estimated value, a null symbol power calculation unit that calculates a null symbol power estimated value, a null symbol spectrum calculation unit that calculates a null symbol spectrum from a null symbol signal, and an interference center frequency estimation unit that eliminates the effect of an image for an interference in calculation of an interference bandwidth when is calculating an interference center frequency estimated value, using a data symbol signal, the data symbol power estimated value, the null symbol power estimated value, and the null symbol spectrum.

The method is for identifying a signal and its image signal input to the heterodyne frequency sweep system. Comparing to a traditional heterodyne frequency sweep technology, a mixing module with a positive and negative sign filters (PNS filters) is introduced, and the detection and identification module is added, and the typical low-pass filter in the input module is removed. According to the timing order sequence of the signal output from the intermediate frequency (IF) filter and PNS filters, a signal and its image signal can be identified. The bandwidth of the heterodyne frequency sweep system is not limited by the cut-off frequency of the low-pass filter (LPF) of the traditional heterodyne frequency sweep system.

An apparatus for determining unknown radio frequencies is described. The apparatus modulates a first optical signal from tunable optical source with RF signal that includes unknown center frequency value to generate modulated optical signal. The apparatus combines modulated optical signal with second optical signal to generate combined modulated optical signal. The apparatus receives output electrical signal from photodetector in response to receiving combined modulated optical signal at photodetector, splits output electrical signal into first output electrical signal and second output electrical signal, and filter first output electrical signal by applying first optical bandpass filter centered to generate first filtered RF signal. The apparatus tunes tunable optical source to first beat frequency value to determine unknown frequency value of RF signal.

An interference cancellation device includes a data symbol extraction unit that extracts a data symbol portion from a received signal, a null symbol extraction unit that extracts a null symbol portion from the received signal, a data symbol power calculation unit that calculates a data symbol power estimated value, a null symbol power calculation unit that calculates a null symbol power estimated value, a null symbol spectrum calculation unit that calculates a null symbol spectrum from a null symbol signal, and an interference center frequency estimation unit that eliminates the effect of an image for an interference in calculation of an interference bandwidth when is calculating an interference center frequency estimated value, using a data symbol signal, the data symbol power estimated value, the null symbol power estimated value, and the null symbol spectrum.

An accessory device has a test port, an instrument port to connect to an instrument having an operating bandwidth, and one or more configurable signal paths connectable between the test port and the instrument port to convert a signal from the test port having a first frequency range to a signal having a second frequency range different than the first frequency range. A test and measurement system has a test and measurement instrument having an operating bandwidth, and an accessory device. The accessory device has a first instrument port to connect the accessory device to the test and measurement instrument, a test port to connect the accessory device to a device under test, and one or more configurable signal paths connectable between the test port and the instrument port to down-convert a signal from the test port having a first frequency range to a signal having a second frequency range lower than the first frequency range.

A device includes a first oscillator, a second oscillator and a frequency comparison block. The first oscillator includes a first LC tank circuit and is designed to generate first sustained oscillations at a first resonant frequency. The second oscillator includes a second LC tank circuit and is designed to generate second sustained oscillations at a second resonant frequency. The frequency comparison block is designed to perform a comparison of the frequencies of the second sustained oscillations and the first sustained oscillations to determine a change in inductance in one of a first inductor of the first LC tank circuit and a second inductor of the second LC tank circuit. One of the oscillators serves as a reference oscillator, and enables determination of the change in inductance to be immune to changes in environmental conditions.

A device includes a first oscillator, a second oscillator and a frequency comparison block. The first oscillator includes a first LC tank circuit and is designed to generate first sustained oscillations at a first resonant frequency. The second oscillator includes a second LC tank circuit and is designed to generate second sustained oscillations at a second resonant frequency. The frequency comparison block is designed to perform a comparison of the frequencies of the second sustained oscillations and the first sustained oscillations to determine a change in inductance in one of a first inductor of the first LC tank circuit and a second inductor of the second LC tank circuit. One of the oscillators serves as a reference oscillator, and enables determination of the change in inductance to be immune to changes in environmental conditions.

A device includes a first oscillator, a second oscillator and a frequency comparison block. The first oscillator includes a first LC tank circuit and is designed to generate first sustained oscillations at a first resonant frequency. The second oscillator includes a second LC tank circuit and is designed to generate second sustained oscillations at a second resonant frequency. The frequency comparison block is designed to perform a comparison of the frequencies of the second sustained oscillations and the first sustained oscillations to determine a change in inductance in one of a first inductor of the first LC tank circuit and a second inductor of the second LC tank circuit. One of the oscillators serves as a reference oscillator, and enables determination of the change in inductance to be immune to changes in environmental conditions.

A method for estimating a property of a signal (1) sensed in an electrical system, comprises the steps of sensing the signal (1) and estimating a fundamental period of a fundamental of the signal (1) by comparing the sensed signal (1) with at least one threshold (2) to detect threshold crossings and estimating the fundamental period from the threshold crossings. The signal property is then estimated from the fundamental period and/or from the sensed signal (1) during an interval of a length of the fundamental period. An electronic device according to the invention comprises a micro controller and/or an analogue circuitry which performs the method for estimating a property of a signal. Preferably, the micro controller and/or analogue circuitry controls other parts of the electronic device depending on the results obtained by the method for estimating a property of a signal.

A method for estimating a property of a signal (1) sensed in an electrical system, comprises the steps of sensing the signal (1) and estimating a fundamental period of a fundamental of the signal (1) by comparing the sensed signal (1) with at least one threshold (2) to detect threshold crossings and estimating the fundamental period from the threshold crossings. The signal property is then estimated from the fundamental period and/or from the sensed signal (1) during an interval of a length of the fundamental period. An electronic device according to the invention comprises a micro controller and/or an analogue circuitry which performs the method for estimating a property of a signal. Preferably, the micro controller and/or analogue circuitry controls other parts of the electronic device depending on the results obtained by the method for estimating a property of a signal.