904 research outputs found
Comprehension of Morse Code Predicted by Item Recall From Short-Term Memory
Published online: Sep 7, 2021Purpose: Morse code as a form of communication became
widely used for telegraphy, radio and maritime communication,
and military operations, and remains popular with ham radio
operators. Some skilled users of Morse code are able to
comprehend a full sentence as they listen to it, while others
must first transcribe the sentence into its written letter
sequence. Morse thus provides an interesting opportunity
to examine comprehension differences in the context of
skilled acoustic perception. Measures of comprehension
and short-term memory show a strong correlation across
multiple forms of communication. This study tests whether
this relationship holds for Morse and investigates its underlying
basis. Our analyses examine Morse and speech immediate
serial recall, focusing on established markers of echoic
storage, phonological-articulatory coding, and lexicalsemantic
support. We show a relationship between Morse
short-term memory and Morse comprehension that is not
explained by Morse perceptual fluency. In addition, we
find that poorer serial recall for Morse compared to speech
is primarily due to poorer item memory for Morse, indicating
differences in lexical-semantic support. Interestingly,
individual differences in speech item memory are also
predictive of individual differences in Morse comprehension.
Conclusions: We point to a psycholinguistic framework
to account for these results, concluding that Morse functions
like “reading for the ears” (Maier et al., 2004) and that
underlying differences in the integration of phonological
and lexical-semantic knowledge impact both short-term
memory and comprehension. The results provide insight
into individual differences in the comprehension of degraded
speech and strategies that build comprehension through
listening experience.This work was supported by NIMH Grant RO1-MH59256 JAF). Sara Guediche, now at BCBL, is supported by funding from
European Union’s Horizon 2020 Marie Sklodowska-Curie Grant
agreement No-79954, the Basque Government through the Basque
Excellence Research Centers 2018-2021 program, and the Spanish
State Agency Severo Ochoa excellence accreditation SEV-2015-0490
(awarded to the BCBL). Thanks to Marina Kalashnikova and
members of the Spoken Language Interest Group for helpful discussions.
The authors thank Maryam Khatami, Jody Manners,
Corrine Durisko, and Tanisha Hill-Jarrett for assisting with project.
We also thank ham radio community, especially Paul Jacob
High accuracy switched-current circuits using an improved dynamic mirror
The switched-current technique, a recently developed circuit approach to analog signal processing, has emerged as an alternative/compliment to the well established switched-capacitor circuit technique. High speed switched-current circuits offer potential cost and power savings over slower switched-capacitor circuits. Accuracy improvements are a primary concern at this stage in the development of the switched-current technique. Use of the dynamic current mirror has produced circuits that are insensitive to transistor matching errors. The dynamic current mirror has been limited by other sources of error including clock-feedthrough and voltage transient errors. In this paper we present an improved switched-current building block using the dynamic current mirror. Utilizing current feedback the errors due to current imbalance in the dynamic current mirror are reduced. Simulations indicate that this feedback can reduce total harmonic distortion by as much as 9 dB. Additionally, we have developed a clock-feedthrough reduction scheme for which simulations reveal a potential 10 dB total harmonic distortion improvement. The clock-feedthrough reduction scheme also significantly reduces offset errors and allows for cancellation with a constant current source. Experimental results confirm the simulated improvements
Speech perception under adverse conditions: Insights from behavioral, computational, and neuroscience research
Adult speech perception reflects the long-term regularities of the native language, but it is also flexible such that it accommodates and adapts to adverse listening conditions and short-term deviations from native-language norms. The purpose of this article is to examine how the broader neuroscience literature can inform and advance research efforts in understanding the neural basis of flexibility and adaptive plasticity in speech perception. Specifically, we highlight the potential role of learning algorithms that rely on prediction error signals and discuss specific neural structures that are likely to contribute to such learning. To this end, we review behavioral studies, computational accounts, and neuroimaging findings related to adaptive plasticity in speech perception. Already, a few studies have alluded to a potential role of these mechanisms in adaptive plasticity in speech perception. Furthermore, we consider research topics in neuroscience that offer insight into how perception can be adaptively tuned to short-term deviations while balancing the need to maintain stability in the perception of learned long-term regularities. Consideration of the application and limitations of these algorithms in characterizing flexible speech perception under adverse conditions promises to inform theoretical models of speech. © 2014 Guediche, Blumstein, Fiez and Holt
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