Agilent Technologies, Inc.

Keysight Technologies, Inc.

Robin A Bordow

Thomas A Gray

Xiangzhou Joe Zhang

A real-time spectrum analyzer for measuring time domain data of an input signal includes an ADC, a resampler and a density histogram memory unit. The ADC has a first sample rate and is configured to acquire and digitize the input signal at the first sample rate to provide first samples. The resampler has a second sample rate and is configured to acquire the first samples at the second sample rate to provide second samples grouped in sample sets, where the second sample rate is selected so that each sample set includes an integer number of second samples per an integer number of periods at a frequency of interest of the input signal. The density histogram memory unit is configured to store at least a portion of the second samples output by the resampler for generating a continuous real-time gap-free density histogram corresponding to the time domain data.

Real-time gap free time domain density histogram display with arbitrary sample rate

An electrical signal is processed by digitizing the electrical signal to produce a stream of digitized data in the time domain, wherein the stream has an original frequency spectrum, transmitting the stream to N signal paths (N&#x3e;1), and down-converting and filtering the stream in each of the N signal paths to produce N streams of digitized data in the time domain, wherein the N streams have N frequency spectra, respectively, and the N frequency spectra cover N different portions of the original frequency spectrum, respectively.

Conversion of analog signal into multiple time-domain data streams corresponding to different portions of frequency spectrum and recombination of those streams into single-time domain stream

A real-time spectrum analyzer for measuring time domain data sampled from an input signal includes a processing unit and a density histogram memory unit. The processing unit includes an FFT engine, a frequency mask detector and a frequency mask gate. The FFT engine performs FFTs on the sampled time domain data to provide FFT spectra, each FFT spectrum including multiple FFT points. The frequency mask detector determines whether each FFT point in each spectrum meets a trigger condition, and generates gate control signals corresponding to the FFT spectra based on the determinations. The frequency mask gate receives the FFT spectra and the gate control signals, and outputs only select FFT spectra that contain at least one FFT point that meets the trigger condition in response to the corresponding gate control signal. The density histogram memory unit stores the select FFT spectra for generating in a density histogram.

Real-time spectrum analyzer including frequency mask gate and method of operating the same

A method of operating an electronic system comprises storing information corresponding to an input data stream in a first memory having a first operating rate, detecting an overflow condition of the first memory, generating overflow information in response to the detection of the overflow condition, storing the overflow information in a second memory having a second operating rate slower than the first operating rate, transferring the overflow information from the detector to a third memory at a first transfer rate corresponding to the first operating rate, temporarily storing the overflow information in the third memory, and transferring the stored overflow information to the second memory at a second transfer rate corresponding to the second operating rate, and combining the information stored in the first memory with the overflow information stored in the second memory to produce an output data stream.

Electronic system subject to memory overflow condition

A method and apparatus for making multiple independent measurements of events from multiple measurement setups entered at a single time. A measurement instrument receives N measurement setups to make N measurements of an input signal, where N is an integer greater than or equal to one. A memory is divided into N partitions, each of the N partitions corresponding to one of the N measurements. A first measurement is run on the input signal, the first measurement selected from the N measurements. The data from the first measurement is stored in a first partition selected from the N partitions.

Multiple independent measurements of events from multiple measurement setups entered at a single time

An integrated calibration source and analog-to-digital converter are referenced to an analog ground. The calibration source provides a comb spectrum established by a sequence of bits that are repeatedly played back.

Integrated calibration source and analog-to-digital converter

A dynamic model of non-linear tuning behavior is used to tune a tunable device. The model quantifies a difference between a tuning characteristic of an ideal device and an actual tuning characteristic of the device. The model adjusts the tuning according to the difference. A method of compensated tuning of tunable device comprises employing a dynamic model of the tunable device to produce a compensated tuning control input to the tunable device during tuning. A tuning compensator for a tunable device comprises the dynamic model that is employed with an input tuning command to generate a compensated tuning command. A tuning-compensated YTF comprises a dynamic model-based tuning compensator and a YTF. A spectrum analyzer having a tuning-compensated preselector comprises a YTF preselector, a frequency converter, a video signal processor unit, a tuning compensator, and a controller. The tuning compensator uses the dynamic model to tune the preselector.

Dynamic model-based compensated tuning of a tunable device

A first system includes a converter, complex signal generator, exponentiator, FFT module and processor to estimate carrier frequency of a high symbol rate quadrature amplutide modulated (QAM) signal relative to a target carrier frequency. The converter converts the applied QAM signal to an intermediate frequency (IF) signal and digitizes the IF signal at a predesignated sample rate. The complex signal generator extracts a real component of the digitized IF signal, provides an imaginary component of the digitized IF signal and then combines the real component and the imaginary component in a complex signal. The exponentiator, raises the complex signal to a predesignated power and the FFT module performs a Fast Fourier Transform (FFT), having a predetermined number of samples, on the complex signal as raised to the predesignated power. The processor, takes the magnitude of the resulting FFT, extracts the index of a sample within the resulting FFT having the greatest magnitude and estimates the carrier frequency of the applied QAM signal relative to a target carrier frequency based on the predesignated power, the extracted index and the predesignated sample rate. In a second system a quadrature downconverter replaces the complex signal generator.

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Petaluma, CA, United States of America

Robin A Bordow