Improving the Dynamic Range of Spectrum Measurements by Compensating for the Effects of Phase Noise and Thermal Noise

2001 ◽  
Author(s):  
Benjamin R. Zarlingo ◽  
Wing J. Mar
Keyword(s):  
Phase Noise ◽  
Thermal Noise ◽  
Dynamic Range ◽  
Spectrum Measurements

scholarly journals State-of-the-art VLBI imaging: 3C345

1991 ◽  
Vol 131 ◽  
pp. 354-357
Author(s):  
Ann E. Wehrle ◽  
Stephen C. Unwin
Keyword(s):  
Thermal Noise ◽  
Dynamic Range ◽  
State Of The Art ◽  
High Dynamic Range ◽  
Instrumental Effects ◽  
High Dynamic ◽  
Low Dynamic Range ◽  
Very High

AbstractMost VLBI images have low dynamic range because they are limited by instrumental effects such as calibration errors and poor u, v-coverage. We outline the method used to make a new image of the bright quasar 3C345 which has very high dynamic range (peak-to-noise of 5000:1) and which is limited by the thermal noise, not instrumental errors. Both the Caltech VLBI package and the NRAO AIPS package were required to manipulate the data.

Phase noise and dynamic range of analog fiber links using electroabsorption modulators

1996 ◽  
Author(s):  
Robert B. Welstand ◽  
Richard J. Orazi ◽  
Chen K. Sun ◽  
Hemonth G. Rao ◽  
Yet Zen Liu ◽  
...  
Keyword(s):  
Phase Noise ◽  
Dynamic Range ◽  
Electroabsorption Modulators ◽  
Fiber Links

scholarly journals Implementation of a Cross-Spectrum FFT Analyzer for a Phase-Noise Test System in a Low-Cost FPGA

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Patrick Fleischmann ◽  
Heinz Mathis ◽  
Jakub Kucera ◽  
Stefan Dahinden
Keyword(s):  
Phase Noise ◽  
Cross Correlation ◽  
Dynamic Range ◽  
Low Cost ◽  
Test System ◽  
Low Noise ◽  
Noise Levels ◽  
High Quality ◽  
Cross Spectrum ◽  
The Cross

The cross-correlation method allows phase-noise measurements of high-quality devices with very low noise levels, using reference sources with higher noise levels than the device under test. To implement this method, a phase-noise analyzer needs to compute the cross-spectral density, that is, the Fourier transform of the cross-correlation, of two time series over a wide frequency range, from fractions of Hz to tens of MHz. Furthermore, the analyzer requires a high dynamic range to accommodate the phase noise of high-quality oscillators that may fall off by more than 100 dB from close-in noise to the noise floor at large frequency offsets. This paper describes the efficient implementation of a cross-spectrum analyzer in a low-cost FPGA, as part of a modern phase-noise analyzer with very fast measurement time.

Dynamic range of an optical amplifier cascade in an ASK system with significant phase noise

1992 ◽  
Vol 4 (12) ◽  
pp. 1354-1357 ◽  
Author(s):  
J. Farre ◽  
E. Bodtker ◽  
G. Jacobsen ◽  
K.E. Stubkjaer
Keyword(s):  
Phase Noise ◽  
Dynamic Range ◽  
Optical Amplifier ◽  
Significant Phase

scholarly journals A Capacitive Feedback Transimpedance Amplifier with a DC Feedback Loop Using a Transistor for High DC Dynamic Range

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4716
Author(s):  
Jung-hoon Noh
Keyword(s):  
Feedback Loop ◽  
Thermal Noise ◽  
Dynamic Range ◽  
System Stability ◽  
Design Parameters ◽  
Transimpedance Amplifier ◽  
Simple Method ◽  
Noise Current ◽  
Dc Component ◽  
Capacitive Feedback

This study proposes a capacitive feedback transimpedance amplifier (CF-TIA) using a transistor in the direct current (DC) feedback loop for high DC dynamic range. In some applications, the background DC input can vary widely from the minimum to the maximum, and TIA have to sense the target signal even on the top of the maximum DC input. In a conventional CF-TIA, however, the allowable DC input is constrained by the value of the resistor in the DC feedback loop. To allow a fairly high DC input, the resistor is set to a very low value. This causes the thermal noise current to increase significantly. The increased thermal noise is always present even in the minimum DC input, thus degrading the overall noise performance. The circuit proposed herein overcomes this shortcoming by using the transistor instead of the resistor. The adverse effect of the parasitic capacitance of the transistor on system stability is compensated for as well. Then, the analyses of the overall frequency response and design parameters, including the cut-off frequency and attenuation ratio associated with system stability, are presented for the proposed circuit. In addition, in order to cope with the problem that stability is dependent on the amount of DC input, a simple method for ensuring system stability regardless of DC component value is introduced. The presented analyses and the method are generalized for all CF-TIA applications.

scholarly journals Ultralow-noise microwave extraction from optical frequency combs using photocurrent pulse shaping with balanced photodetection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Minji Hyun ◽  
Chan-Gi Jeon ◽  
Jungwon Kim
Keyword(s):  
Phase Noise ◽  
Pulse Shaping ◽  
Thermal Noise ◽  
Optical Power ◽  
High Peak Power ◽  
Optical Frequency ◽  
Optical Pulses ◽  
Noise Sources ◽  
Optical Frequency Combs ◽  
Frequency Combs

AbstractThe phase noise of microwaves extracted from optical frequency combs is fundamentally limited by thermal and shot noise, which is inherent in photodetection. Saturation of a photodiode due to the high peak power of ultrashort optical pulses, however, prohibits further scaling of white phase noise by increasing incident optical power. Here we demonstrate that the photocurrent pulse shaping via balanced photodetection, which is accomplished by replacing a single photodiode with a balanced photodetector (BPD) and delaying one of the optical pulses, provides a simple and efficient optical-to-electrical interface to increase achievable microwave power and reduces the corresponding thermal noise-limited phase noise by 6-dB. By analysing contributing noise sources, we also show that the thermal noise floor can reach − 166 dBc/Hz even at a low photocurrent of 2-mA (4-mW optical input per photodiode) when using a p-i-n BPD. This finding may be useful for on-chip microwave generation, which consists of standard p-i-n structure photodiodes with relatively low saturation optical power.

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