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14 September 1998 Techniques for pixel-level analog-to-digital conversion
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Two techniques for performing pixel level analog to digital conversion (ADC) are reviewed. The first is an over-sampling technique which uses a one bit first order (Sigma) (Delta) modulator for each 2 X 2 block of pixels to directly convert photocharge to bits. Each modulator is implemented using 17 transistors. The second technique is a Nyquist rate multi-channel-bit-serial (MCBS) ADC. The technique use successive comparisons to convert the pixel voltage to bits. Results obtained from implementations of these ADC techniques are presented. The techniques are compared based on size, charge handling capacity, FPN, noise sensitivity, data throughput, quantization, memory/processing, and power dissipation requirements for both visible an dIR imagers. From the comparison it appears that the (Sigma) (Delta) ADC is better suited to IR imagers, while the MCBS ADC is better suited to imagers in the visible range.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Boyd A. Fowler, Abbas El Gamal, and David X. D. Yang "Techniques for pixel-level analog-to-digital conversion", Proc. SPIE 3360, Infrared Readout Electronics IV, (14 September 1998);


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