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Anantha P Chandrakasan - One of the best experts on this subject based on the ideXlab platform.

  • a noise efficient 36 nv surd hz chopper amplifier using an inverter based 0 2 v supply input stage
    IEEE Journal of Solid-state Circuits, 2017
    Co-Authors: Frank M Yaul, Anantha P Chandrakasan
    Abstract:

    This paper presents an analog front end (AFE) that achieves a high noise efficiency by using a chopper amplifier with a 0.2-V supply inverter-based input stage followed by a 0.8-V supply stage. The high input-stage current needed to reduce the input-referred noise is drawn from the 0.2-V supply, significantly reducing power consumption. The 0.8 V stage provides high gain and signal swing, improving linearity. Biasing and common-mode rejection techniques for the ultra-low-voltage stage are presented. The AFE is implemented in a 0.18 $\mu \text{m}$ CMOS process and integrates the chopper low-noise instrumentation amplifier, a programmable-gain amplifier, and an Antialiasing Filter. The AFE consumes 0.79 $\mu \text{W}$ and achieves a competitive power efficiency factor (PEF) of 1.6 and an input noise of 0.94 $\mu \text{V}_{\text {rms}}$ integrated from 0.5 to 670 Hz while maintaining a 36 nV/ $\surd $ Hz input noise density down to 0.5 Hz. The included 0.8/0.2-V buck converter may be used to provide the 0.2-V supply at 72%–74% efficiency without significantly increasing noise, yielding a PEF of 1.8.

  • a noise efficient 36 nv surd hz chopper amplifier using an inverter based 0 2 v supply input stage
    IEEE Journal of Solid-state Circuits, 2017
    Co-Authors: Frank M Yaul, Anantha P Chandrakasan
    Abstract:

    This paper presents an analog front end (AFE) that achieves a high noise efficiency by using a chopper amplifier with a 0.2-V supply inverter-based input stage followed by a 0.8-V supply stage. The high input-stage current needed to reduce the input-referred noise is drawn from the 0.2-V supply, significantly reducing power consumption. The 0.8 V stage provides high gain and signal swing, improving linearity. Biasing and common-mode rejection techniques for the ultra-low-voltage stage are presented. The AFE is implemented in a 0.18 $\mu \text{m}$ CMOS process and integrates the chopper low-noise instrumentation amplifier, a programmable-gain amplifier, and an Antialiasing Filter. The AFE consumes 0.79 $\mu \text{W}$ and achieves a competitive power efficiency factor (PEF) of 1.6 and an input noise of 0.94 $\mu \text{V}_{\text {rms}}$ integrated from 0.5 to 670 Hz while maintaining a 36 nV/ $\surd $ Hz input noise density down to 0.5 Hz. The included 0.8/0.2-V buck converter may be used to provide the 0.2-V supply at 72%–74% efficiency without significantly increasing noise, yielding a PEF of 1.8.

Frank M Yaul - One of the best experts on this subject based on the ideXlab platform.

  • a noise efficient 36 nv surd hz chopper amplifier using an inverter based 0 2 v supply input stage
    IEEE Journal of Solid-state Circuits, 2017
    Co-Authors: Frank M Yaul, Anantha P Chandrakasan
    Abstract:

    This paper presents an analog front end (AFE) that achieves a high noise efficiency by using a chopper amplifier with a 0.2-V supply inverter-based input stage followed by a 0.8-V supply stage. The high input-stage current needed to reduce the input-referred noise is drawn from the 0.2-V supply, significantly reducing power consumption. The 0.8 V stage provides high gain and signal swing, improving linearity. Biasing and common-mode rejection techniques for the ultra-low-voltage stage are presented. The AFE is implemented in a 0.18 $\mu \text{m}$ CMOS process and integrates the chopper low-noise instrumentation amplifier, a programmable-gain amplifier, and an Antialiasing Filter. The AFE consumes 0.79 $\mu \text{W}$ and achieves a competitive power efficiency factor (PEF) of 1.6 and an input noise of 0.94 $\mu \text{V}_{\text {rms}}$ integrated from 0.5 to 670 Hz while maintaining a 36 nV/ $\surd $ Hz input noise density down to 0.5 Hz. The included 0.8/0.2-V buck converter may be used to provide the 0.2-V supply at 72%–74% efficiency without significantly increasing noise, yielding a PEF of 1.8.

  • a noise efficient 36 nv surd hz chopper amplifier using an inverter based 0 2 v supply input stage
    IEEE Journal of Solid-state Circuits, 2017
    Co-Authors: Frank M Yaul, Anantha P Chandrakasan
    Abstract:

    This paper presents an analog front end (AFE) that achieves a high noise efficiency by using a chopper amplifier with a 0.2-V supply inverter-based input stage followed by a 0.8-V supply stage. The high input-stage current needed to reduce the input-referred noise is drawn from the 0.2-V supply, significantly reducing power consumption. The 0.8 V stage provides high gain and signal swing, improving linearity. Biasing and common-mode rejection techniques for the ultra-low-voltage stage are presented. The AFE is implemented in a 0.18 $\mu \text{m}$ CMOS process and integrates the chopper low-noise instrumentation amplifier, a programmable-gain amplifier, and an Antialiasing Filter. The AFE consumes 0.79 $\mu \text{W}$ and achieves a competitive power efficiency factor (PEF) of 1.6 and an input noise of 0.94 $\mu \text{V}_{\text {rms}}$ integrated from 0.5 to 670 Hz while maintaining a 36 nV/ $\surd $ Hz input noise density down to 0.5 Hz. The included 0.8/0.2-V buck converter may be used to provide the 0.2-V supply at 72%–74% efficiency without significantly increasing noise, yielding a PEF of 1.8.

Ketan Tang - One of the best experts on this subject based on the ideXlab platform.

  • Antialiasing Filter Design for Subpixel Downsampling via Frequency-Domain Analysis
    2013
    Co-Authors: Lu Fang, Ketan Tang, Aggelos K. Katsaggelos
    Abstract:

    Abstract—In this paper, we are concerned with image downsampling using subpixel techniques to achieve superior sharpness for small liquid crystal displays (LCDs). Such a problem exists when a high-resolution image or video is to be displayed on low-resolution display terminals. Limited by the low-resolution display, we have to shrink the image. Signal-processing theory tells us that optimal decimation requires low-pass Filtering with a suitable cutoff frequency, followed by downsampling. In doing so, we need to remove many useful image details causing blurring. Subpixel-based downsampling, taking advantage of the fact that each pixel on a color LCD is actually composed of individual red, green, and blue subpixel stripes, can provide apparent higher resolution. In this paper, we use frequency-domain analysis to explain what happens in subpixel-based downsampling and why it is possible to achieve a higher apparent resolution. According to our frequency-domain analysis and observation, the cutoff frequency of the low-pass Filter for subpixel-based decimation can be effectively extended beyond the Nyquist frequency using a novel Antialiasing Filter. Applying the proposed Filters to two existing subpixel downsampling schemes called direct subpixel-based downsampling (DSD) and diagonal DSD (DDSD), we obtain two improved schemes, i.e., DSD based on frequency-domain analysis (DSD-FA) and DDSD based on frequency-domain analysis (DDSD-FA). Experimental results verify that the proposed DSD-FA and DDSD-FA can provide superior results, compared with existing subpixel or pixel-based downsampling methods. Index Terms—Downsampling, frequency analysis, subpixel rendering. I

  • Antialiasing Filter design for subpixel downsampling via frequency domain analysis
    IEEE Transactions on Image Processing, 2012
    Co-Authors: Lu Fang, Oscar C. Au, Ketan Tang
    Abstract:

    In this paper, we are concerned with image downsampling using subpixel techniques to achieve superior sharpness for small liquid crystal displays (LCDs). Such a problem exists when a high-resolution image or video is to be displayed on low-resolution display terminals. Limited by the low-resolution display, we have to shrink the image. Signal-processing theory tells us that optimal decimation requires low-pass Filtering with a suitable cutoff frequency, followed by downsampling. In doing so, we need to remove many useful image details causing blurring. Subpixel-based downsampling, taking advantage of the fact that each pixel on a color LCD is actually composed of individual red, green, and blue subpixel stripes, can provide apparent higher resolution. In this paper, we use frequency-domain analysis to explain what happens in subpixel-based downsampling and why it is possible to achieve a higher apparent resolution. According to our frequency-domain analysis and observation, the cutoff frequency of the low-pass Filter for subpixel-based decimation can be effectively extended beyond the Nyquist frequency using a novel Antialiasing Filter. Applying the proposed Filters to two existing subpixel downsampling schemes called direct subpixel-based downsampling (DSD) and diagonal DSD (DDSD), we obtain two improved schemes, i.e., DSD based on frequency-domain analysis (DSD-FA) and DDSD based on frequency-domain analysis (DDSD-FA). Experimental results verify that the proposed DSD-FA and DDSD-FA can provide superior results, compared with existing subpixel or pixel-based downsampling methods.

Lu Fang - One of the best experts on this subject based on the ideXlab platform.

  • Antialiasing Filter Design for Subpixel Downsampling via Frequency-Domain Analysis
    2013
    Co-Authors: Lu Fang, Ketan Tang, Aggelos K. Katsaggelos
    Abstract:

    Abstract—In this paper, we are concerned with image downsampling using subpixel techniques to achieve superior sharpness for small liquid crystal displays (LCDs). Such a problem exists when a high-resolution image or video is to be displayed on low-resolution display terminals. Limited by the low-resolution display, we have to shrink the image. Signal-processing theory tells us that optimal decimation requires low-pass Filtering with a suitable cutoff frequency, followed by downsampling. In doing so, we need to remove many useful image details causing blurring. Subpixel-based downsampling, taking advantage of the fact that each pixel on a color LCD is actually composed of individual red, green, and blue subpixel stripes, can provide apparent higher resolution. In this paper, we use frequency-domain analysis to explain what happens in subpixel-based downsampling and why it is possible to achieve a higher apparent resolution. According to our frequency-domain analysis and observation, the cutoff frequency of the low-pass Filter for subpixel-based decimation can be effectively extended beyond the Nyquist frequency using a novel Antialiasing Filter. Applying the proposed Filters to two existing subpixel downsampling schemes called direct subpixel-based downsampling (DSD) and diagonal DSD (DDSD), we obtain two improved schemes, i.e., DSD based on frequency-domain analysis (DSD-FA) and DDSD based on frequency-domain analysis (DDSD-FA). Experimental results verify that the proposed DSD-FA and DDSD-FA can provide superior results, compared with existing subpixel or pixel-based downsampling methods. Index Terms—Downsampling, frequency analysis, subpixel rendering. I

  • Antialiasing Filter design for subpixel downsampling via frequency domain analysis
    IEEE Transactions on Image Processing, 2012
    Co-Authors: Lu Fang, Oscar C. Au, Ketan Tang
    Abstract:

    In this paper, we are concerned with image downsampling using subpixel techniques to achieve superior sharpness for small liquid crystal displays (LCDs). Such a problem exists when a high-resolution image or video is to be displayed on low-resolution display terminals. Limited by the low-resolution display, we have to shrink the image. Signal-processing theory tells us that optimal decimation requires low-pass Filtering with a suitable cutoff frequency, followed by downsampling. In doing so, we need to remove many useful image details causing blurring. Subpixel-based downsampling, taking advantage of the fact that each pixel on a color LCD is actually composed of individual red, green, and blue subpixel stripes, can provide apparent higher resolution. In this paper, we use frequency-domain analysis to explain what happens in subpixel-based downsampling and why it is possible to achieve a higher apparent resolution. According to our frequency-domain analysis and observation, the cutoff frequency of the low-pass Filter for subpixel-based decimation can be effectively extended beyond the Nyquist frequency using a novel Antialiasing Filter. Applying the proposed Filters to two existing subpixel downsampling schemes called direct subpixel-based downsampling (DSD) and diagonal DSD (DDSD), we obtain two improved schemes, i.e., DSD based on frequency-domain analysis (DSD-FA) and DDSD based on frequency-domain analysis (DDSD-FA). Experimental results verify that the proposed DSD-FA and DDSD-FA can provide superior results, compared with existing subpixel or pixel-based downsampling methods.

Camilla Brekke - One of the best experts on this subject based on the ideXlab platform.

  • Statistical models for constant false alarm rate ship detection with the sublook correlation magnitude
    2012 IEEE International Geoscience and Remote Sensing Symposium, 2012
    Co-Authors: Stian Normann Anfinsen, Camilla Brekke
    Abstract:

    This paper presents statistical models for the sublook correlation magnitude (SCM), a test statistic for ship detection that can be produced from single-look complex (SLC) synthetic aperture radar (SAR) data. The SCM is extracted from the complex correlation between two subaperture images and provides enhanced contrast between coherent structures, such as marine vessels, and sea clutter. A modified SCM algorithm has been proposed, which introduces an Antialiasing Filter in order to allow overlapping sublook spectra. The consequences for the statistical modelling are discussed. We perform an empirical study which validates the use of the K distribution and the Fisher distribution as probability density functions for sea clutter in SCM images. This lays the groundwork for constant false alarm rate (CFAR) detection with SCM images. The fit of the models are assessed with real data.

  • Statistical models for constant false alarm rate ship detection with the sublook correlation magnitude
    2012
    Co-Authors: Stian Normann Anfinsen, Camilla Brekke
    Abstract:

    This paper presents statistical models for the subaperture cross-correlation magnitude (SCM), a test statistic for ship detection which can be produced from single-look complex (SLC) synthetic aperture radar (SAR) data. The SCM is extracted from the complex cross-correlation between two subaperture images and provides enhanced contrast between coherent structures, such as marine vessels, and sea clutter. A modified SCM algorithm has been proposed, which in-troduces an Antialiasing Filter in order to allow overlapping sublook spectra. The consequences for the statistical mod-elling are discussed. We perform an empirical study which validates the use of the K distribution and the Fisher dis-tribution as probability density functions for sea clutter in SCM images. This lays the groundwork for constant false alarm rate (CFAR) detection with SCM images. The fit of the models are assessed with real data. Index Terms — Synthetic aperture radar, detection algo-rithms, marine vehicles, subaperture processing 1