Abstract-A mathematical bit error rate (BER) model for upsets in memories protected by error-correcting codes (ECCs) and scrubbing is derived. This model is compared with expected upset rates for sub-100-nm SRAM memories in space environments. Because sub-100-nm SRAM memory cells can be upset by a critical charge ( crit ) of 1.1 fC or less, they may exhibit significantly higher upset rates than those reported in earlier technologies. Because of this, single-bit-correcting ECCs may become impractical due to memory scrubbing rate limitations. The overhead needed for protecting memories with a triple-bit-correcting ECC is examined relative to an approximate 2X "process generation" scaling penalty in area, speed, and power.
Modern integrated circuits (ICs) employ a myriad of materials organized at nanoscale dimensions, and certain critical tolerances must be met for them to function. To understand departures from intended functionality, it is essential to examine ICs as manufactured so as to adjust design rules, ideally in a non-destructive way so that imaged structures can be correlated with electrical performance. Electron microscopes can do this on thin regions, or on exposed surfaces, but the required processing alters or even destroys functionality. Microscopy with multi-keV x-rays provides an alternative approach with greater penetration, but the spatial resolution of x-ray imaging lenses has not allowed one to see the required detail in the latest generation of ICs. X-ray ptychography provides a way to obtain images of ICs without lens-imposed resolution limits, with past work delivering 20–40 nm resolution on thinned ICs. We describe a simple model for estimating the required exposure, and use it to estimate the future potential for this technique. Here we show for the first time that this approach can be used to image circuit detail through an unprocessed 300 μm thick silicon wafer, with sub-20 nm detail clearly resolved after mechanical polishing to 240 μm thickness was used to eliminate image contrast caused by Si wafer surface scratches. By using continuous x-ray scanning, massively parallel computation, and a new generation of synchrotron light sources, this should enable entire non-etched ICs to be imaged to 10 nm resolution or better while maintaining their ability to function in electrical tests.
T h i s paper p r e s e n t s t h e r e s u l t s of a s t u d y designed t o i n v e s t i g a t e t h e e f f e c t s o f s u b t r a c t i v e -t y p e n o i s e r e d u c t i o n a l g o r i t h m s on LPC based s p e c t r a l paramet e r e s t i m a t i o n as r e l a t e d t o t h e p e r f o rmance of speech p r o c e s s o r s o p e r a t i n g w i t h i n p u t SNRs o f 1 5 d8. and b e l o w . S u b t r a ct i v e n o i s e p r e -p r o c e s s i n g g r e a t l y i mp r o v e s t h e S N R b u t system performance improvement i s n o t commensurate. LPC s p e c t r a l e s t i m a t i o n i s a f f e c t e d by t h e c h a r a c t e r o f t h e r e s i d u a l n o i s e which e x h i b i t s g r e a t e r v a r i a n c e and s p e c t r a l g r a n u l a r i t y t h a n t h e o r i g i n a l broadband n o i s e . The s t u d y shows t h a t removing l e s s t h a n t h e f u l l amount o f n o i s e and w h i t e ni n g i t improve s p e c t r a l e s t i m a t i o n and speech d e v i c e performance. Techniques and Derformance r e s u l t s a r e p r e s e n t e d . 1. I n t r o d u c t i o n The performance o f most speech r e c o g n i t i o n and p a r a m e t r i c speech c o d i n g systems b e g i n s t o s u f f e r a t s i g n a l -t on o i s e r a t i o s o f 1 5 de. and below. N o i s e i n t e r f e r e s w i t h t h e a c c u r a t e e x t r a c t i o n and m o d e l i n g o f speech s p e c t r a l and t e m p o r a l f e a t u r e s n e c e s s a r y f o r a c c u r a t e r e c o g n i t i o n and c o d i n g . P a r t i c u l a r l y a f f e c t e d a r e p i t c h e x t r a c t i o n , spectrum and f o r m a n t e s t i m a t i o n , and word boundary d e t e c t i o n a l g o r i t h m s . P a t t e r n m a t c h i n g systems s u c h as speech r e c o g n i z e r s and VQ based c o d e r s t e n d t o be a d v e r s e l y a f f e c -. t e d because t h e i n p u t speech f e a t u r e v e c t o r p a t t e r n s a r e supposed t o c o r r e spond w i t h t h e s t o r e d t e m p l a t e s g e n e r a t e d under non-noisy c o n d i t i o n s . Performance g e n e r a l l y i s h i g h l y c o r r e l a t e d w i t h i n p u t SNR a t r a t i o s o f 1 5 d8. and below and u s u a l l y degrades p r e c i p i t o u s l y . I t s t a n d s t o reason t h a t i m p r o v i n g t h e SNR o f t h e i n p u t speech t o p a r a m e t r i c sDeech p r o c e s s o r s by means o f some n o i s e r e d u c t i o n p r e p r o c e s s o r s h o u l d improve d e v i c e performance. V a r i o u s c l a s s e s o f n o i s e r e d u c t i o n a l g o r i t h m s have been developed and implemented o v e r t h e y e a r s w i t h some success. One such c l a s s i s t h e s o e c t r a l / c e p s t r a l s u b t r a c t i o n t e c h n i q u e s and t h e i r v a r i a n t s . I t has been demons t r a t e d [ 1 . 2 , 3 . 4 ] t h a t s u b t r a c t i v e -t y p e broadband n o i s e r e d u c t i o n t e c h n i q u e s can s u b s t a n t i a l l y improve t h e SNR of n o i s y speech and t...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.