Topic
Dynamic range
About: Dynamic range is a research topic. Over the lifetime, 7576 publications have been published within this topic receiving 101739 citations. The topic is also known as: DNR & DR.
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TL;DR: In this article, a fiber-optic acoustic sensor array that is based on the Sagnac interferometer was proposed and compared to acoustic sensor arrays based on Mach-Zehnder (MZ) interferometers, including a stable bias point, a reduced conversion of source phase noise into intensity noise, and a frequency response that matches the ambient ocean noise.
Abstract: We propose a novel design for a fiber-optic acoustic sensor array that is based on the Sagnac interferometer. The performance of this Sagnac sensor array (SSA) design is analyzed and compared to acoustic sensor arrays based on the Mach-Zehnder (MZ) interferometer. It is found that the SSA exhibits several decisive advantages, including a stable bias point, a reduced conversion of source phase noise into intensity noise, and a frequency response that matches the ambient ocean noise. It is also shown that the SSA can be easily designed to have a much larger dynamic range than an MZ-based sensor array. Potential noise sources are analyzed and shown to be manageable. A means for eliminating polarization-induced signal fading is presented. The applicability of time-division, frequency-division, and code-division multiplexing schemes for the proposed design is presented.
51 citations
Patent•
IBM1
TL;DR: In this article, a method for transforming an image from a Low Dynamic Range (LDR) image obtained with a given camera to a High Dynamic Range image was proposed, the method comprising: obtaining the exposure-pixel response curve (21 ) for said given camera converting the LDR image to HSB color space arrays including a Hue array, a Saturation array and a Brigthness array; determining a Radiance array (23, 24 ) by inverse mapping each pixel in said Brightness array using the inverse of the exposurepixel response curves (f-1).
Abstract: The invention provides a method for transforming an image from a Low Dynamic Range (LDR) image obtained with a given camera to a High Dynamic Range (HDR) image, the method comprising:
obtaining the exposure-pixel response curve ( 21 ) for said given camera converting the LDR image to HSB color space arrays ( 22 ), said HSB color space arrays including a Hue array, a Saturation array and a Brigthness array; and determining a Radiance array ( 23, 24 ) by inverse mapping each pixel in said Brightness array using the inverse of the exposure-pixel response curve (f-1).
51 citations
TL;DR: In this article, an analytic formulation of passive intermodulation distortion (PIM) in antennas is presented for PIM introduced by electrothermal modulation of conductivity by current-related losses.
Abstract: An analytic formulation of passive intermodulation distortion (PIM) in antennas is presented for PIM introduced by electro-thermal modulation of conductivity by current-related losses. A silver rectangular patch antenna was fabricated using a sapphire substrate isolating the thermal process from other possible sources. Two-tone testing at 990 MHz using a sweep of the tone separation from 3 Hz to 100 kHz is reported. Both transmitted and reflected PIM are characterized using a high dynamic range two-tone test system incorporating an analog canceler achieving a dynamic range of 125 dB at 1-Hz tone separation for reflection measurements, and 100 dB at 10-Hz tone separation for transmission measurements with each tone set to 32.3 dBm.
51 citations
TL;DR: A novel microwave photonic link (MPL) with an improved spurious-free dynamic range (SFDR) based on a bidirectional use of a polarization modulator (PolM) in a Sagnac loop is proposed and demonstrated.
Abstract: A novel microwave photonic link (MPL) with an improved spurious-free dynamic range (SFDR) based on a bidirectional use of a polarization modulator (PolM) in a Sagnac loop is proposed and demonstrated. The PolM in the loop functions, in conjunction with a polarization controller and a polarization beam combiner, as a Mach Zehnder modulator (MZM), which only modulates the incident light wave along the clockwise direction, leaving the counter-clockwise light wave unmodulated due to the velocity mismatch. Two clockwise intensity-modulated signals along two paths (Path 1 and Path 2) are generated, with one (Path 2) combined with the non-modulated light wave from the counter-clockwise direction to suppress part of the optical carrier. By controlling the power relationship between the two paths, the third-order intermodulation distortion (IMD3) can be fully suppressed, and thus an MPL with improved dynamic range is achieved. A theoretical analysis is presented, which is validated by an experiment. The IMD3 can be suppressed by 50 dB, giving an improvement in SFDR of 16 dB.
51 citations
05 Nov 2007
TL;DR: In this article, the authors present a broad-bandwidth (1 -12 GHz) low-biased external modulation fiber-optic link without preamplifiers that has a gain of 6 dB-14 dB and a noise figure of < 7.S dB everywhere in this broad bandwidth, with a record low noise condition of only 3.4 dB at 2 GHz.
Abstract: We present a broad-bandwidth (1 -12 GHz) low-biased external modulation fiber-optic link without preamplifiers that has a gain of 6 dB-14 dB and a noise figure of < 7.S dB everywhere in this broad bandwidth, with a record low noise figure of only 3.4 dB at 2 GHz. The third-order distortion-limited spurious-free dynamic range (SFDK) of this link within any suboctavc portion of the 1-12 GHz range of operating frequencies is approximately 120 dBHz2/3 in a 1-Hz instantaneous receiver bandwidth. We describe the high-performance components in this link and discuss the extent to which their performance varies with frequency, and show which of these components' frequency-dependent parameters affect which of the three figures of merit (gain, noise figure, and SFDR).
51 citations