A broadband frequency ramp generator for very fast network analysis based on a fractional-N phase locked loop

Mallach, Malte; David-Benjamin, Grys; Musch, Thomas; Storch, Robert

doi:10.1109/eumc.2016.7824520

Cited by 12 publications

(11 citation statements)

References 5 publications

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“…Inside the generators, PLL concepts are used to achieve a high output frequency. Due to the relatively low reference frequency, high divider factors inside the PLL have to be used, which increase the noise transfer from the PLL components to the output [13]. Furthermore, the high thermal capacity of the laboratory signal generators leads to a long-term phase drift between the FPGA clock and the clock of the D-FF.…”

Section: System Overviewmentioning

confidence: 99%

A low-noise and flexible FPGA-based binary signal measurement generator

Notzon

Storch

Musch

et al. 2019

Int. J. Microw. Wireless Technol.

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In the area of electromagnetic metrology, binary coded excitation signals become more and more important and various binary coded sequences are available. The measurement approach is to assess the impulse response function of a device under test by correlating the response signal with the excitation signal. In order to achieve a high measurement reproducibility as well as a high dynamic range, the generated binary coded signals have to provide low-noise. In this contribution, a low-noise signal generator realized with a field programmable gate array is presented. The performance investigation of different kinds of binary coded excitation signals and different correlation concepts have been practically investigated. With a chip rate of 5 Gchip/s, the generator can be utilized for ultra-wideband applications. In order to allow for a low-noise and long-term stable signal generation, a new clock generator concept is presented and results of phase noise measurements are shown. Furthermore, an algorithm to fast and precisely shifting the time lag between two binary coded signals for correlating excitation and response signals with a hardware correlator is presented. Finally, the realized demonstrator system is tested using two commonly used types of binary coded sequences.

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Section: System Overviewmentioning

confidence: 99%

A low-noise and flexible FPGA-based binary signal measurement generator

Notzon

Storch

Musch

et al. 2019

Int. J. Microw. Wireless Technol.

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“…A block diagram of the MWT system including the DAU and a photograph of the eight-port sensor are shown in Figure 6. The synthesizer is one of the key components of the system, and its implementation is similar to that presented in [32]. It generates two signals x I and x II , whose frequencies are linearly varied from the start to the stop frequency, e.g., 0.7 to 5.5 GHz, and differ by a small offset, e.g., ∆ f = 200 kHz.…”

Section: Data Acquisition and Signal Processingmentioning

confidence: 99%

Fast and Precise Soft-Field Electromagnetic Tomography Systems for Multiphase Flow Imaging

et al. 2018

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In the process industry, measurement systems are required for process development and optimization, as well as for monitoring and control. The processes often involve multiphase mixtures or flows that can be analyzed using tomography systems, which visualize the spatial material distribution within a certain measurement domain, e.g., a process pipe. In recent years, we studied the applicability of soft-field electromagnetic tomography methods for multiphase flow imaging, focusing on concepts for high-speed data acquisition and image reconstruction. Different non-intrusive electrical impedance and microwave tomography systems were developed at our institute, which are sensitive to the local contrasts of the electrical properties of the materials. These systems offer a very high measurement and image reconstruction rate of up to 1000 frames per second in conjunction with a dynamic range of up to 120 dB. This paper provides an overview of the underlying concepts and recent improvements in terms of sensor design, data acquisition and signal processing. We introduce a generalized description for modeling the electromagnetic behavior of the different sensors based on the finite element method (FEM) and for the reconstruction of the electrical property distribution using the Gauss-Newton method and Newton's one-step error reconstructor (NOSER) algorithm. Finally, we exemplify the applicability of the systems for different measurement scenarios. They are suitable for the analysis of rapidly-changing inhomogeneous scenarios, where a relatively low spatial resolution is sufficient.

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“…For FMCW signal generation, we utilize our previously developed synthesizer based on fractional-N phase locked loops (PLL) [30], whose block diagram is shown in figure 3. The linear frequency ramp is synthesized in the frequency range from 8.4 GHz to 13.6 GHz (VCO 1 ) and is mixed down to the desired frequency range with a constant frequency of 14 GHz (VCO 2 ).…”

Section: Hardware Conceptmentioning

confidence: 99%

“…To achieve a high accuracy, the synthesizer must generate an analog frequency ramp with a very high linearity [28]. Therefore, in previous work [30] we developed an FMCW synthesizer, which provides a very high ramp linearity as well as a significantly lower ramp sweep time and a larger frequency range than previously published synthesizers [28,29].…”

Section: Introductionmentioning

confidence: 99%

Fast and precise data acquisition for broadband microwave tomography systems

Mallach

Musch

2017

Meas. Sci. Technol.

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Microwave imaging (MWI) is a noninvasive diagnosis method, which has been investigated for a wide range of applications. MWI techniques include radar-based approaches as well as microwave tomography (MWT). One major challenge designing broadband MWI systems is the development of a data acquisition unit that allows for fast broadband scattering parameter measurements with a high measurement precision and a high dynamic range (DR), at reasonable cost. The cost-performance criteria cannot readily be achieved using commercial, continuous wave (CW) vector network analyzers (VNA) or pulse-based systems. Therefore, in this paper we propose a data acquisition unit, based on the well-known method of frequency modulated continuous wave (FMCW) network analysis. It offers fast scattering parameter measurements without compromising the measurement precision and the DR, and is particularly advantageous for MWI systems requiring a high number of frequency samples. A 2-port metadyne prototype electronics with low hardware complexity was developed, which allows very fast, precise, and accurate reflection and transmission measurements in the frequency range from 0.5 GHz to 5.5 GHz. To the best of the authors’ knowledge, a system with combined performance in terms of bandwidth, sweep time (1 ms), DR (80 dB) and maximum signal-to-noise-and-spurious ratio (65 dB) has not previously been reported. The design, the calibration, and the characterization of the prototype electronics are described in detail, and the measurement results are compared to those obtained with commercial high-end CW VNA. The advantages and limitations of the metadyne FMCW technique compared to the heterodyne CW technique are discussed. The applicability of the prototype electronics and the described calibration technique for microwave imaging has been demonstrated based on measurements using an 8-port MWT sensor and a switching matrix.

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A broadband frequency ramp generator for very fast network analysis based on a fractional-N phase locked loop

Cited by 12 publications

References 5 publications

A low-noise and flexible FPGA-based binary signal measurement generator

A low-noise and flexible FPGA-based binary signal measurement generator

Fast and Precise Soft-Field Electromagnetic Tomography Systems for Multiphase Flow Imaging

Fast and precise data acquisition for broadband microwave tomography systems

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