79,561 research outputs found
Analog circuit test based on a digital signature
Production verification of analog circuit specifica-
tions is a challenging task requiring expensive test equipment
and time consuming procedures. This paper presents a method
for low cost on-chip parameter verification based on the analysis
of a digital signature. A 65 nm CMOS on-chip monitor is
proposed and validated in practice. The monitor composes two
signals (x(t), y(t)) and divides the X-Y plane with nonlinear
boundaries in order to generate a digital code for every analog
(x, y) location. A digital signature is obtained using the digital
code and its time duration. A metric defining a discrepancy factor
is used to verify circuit parameters. The method is applied to
detect possible deviations in the natural frequency of a Biquad
filter. Simulated and experimental results show the possibilities
of the proposal.Peer ReviewedPostprint (published version
Verifying analog circuits based on a digital signature
Verification of analog circuit specifications is a
challenging task requiring expensive test equipment and time
consuming procedures. This paper presents a method for low
cost parameter verification based on statistical analysis of
a digital signature. A CMOS on-chip monitor and sampler
circuit generates the digital signature of the CUT. The monitor
composes two signals (x(t); y(t)) and divides the X-Y plane
with nonlinear boundaries in order to generate a digital code for
every analog (x; y) location. A metric to be used to discriminate
the golden and defective signatures is also proposed. The metric
is based on the definition of a discrepancy factor performing
circuit parameter identification via statistical and pre-training
procedures. The proposed method is applied to verify possible
deviations on the natural frequency of a Biquad filter. Simulation
results show the possibilities of the proposal.Postprint (published version
Affinity and dose of TCR engagement yield proportional enhancer and gene activity in CD4+ T cells.
Affinity and dose of T cell receptor (TCR) interaction with antigens govern the magnitude of CD4+ T cell responses, but questions remain regarding the quantitative translation of TCR engagement into downstream signals. We find that while the response of mouse CD4+ T cells to antigenic stimulation is bimodal, activated cells exhibit analog responses proportional to signal strength. Gene expression output reflects TCR signal strength, providing a signature of T cell activation. Expression changes rely on a pre-established enhancer landscape and quantitative acetylation at AP-1 binding sites. Finally, we show that graded expression of activation genes depends on ERK pathway activation, suggesting that an ERK-AP-1 axis plays an important role in translating TCR signal strength into proportional activation of enhancers and genes essential for T cell function
Biocontamination and particulate detection system
A method for determining the characteristics and amount of microscopic contaminants lodged on a photographed surface is disclosed. An image enhanced full color photographic negative and print are taken of the contaminated surface. Three black and white prints are developed subsequently from red, green and blue separation filter overlays of the color negative. Both the color and three monochromatic prints are then scanned to extract in digital form a profile of any contaminant possibly existing on the surface. The resulting profiles are electronically analyzed and compared with data already stored relating to known contaminants
Application of interactive computer graphics in wind-tunnel dynamic model testing
The computer-controlled data-acquisition system recently installed for use with a transonic dynamics tunnel was described. This includes a discussion of the hardware/software features of the system. A subcritical response damping technique, called the combined randomdec/moving-block method, for use in windtunnel-model flutter testing, that has been implemented on the data-acquisition system, is described in some detail. Some results using the method are presented and the importance of using interactive graphics in applying the technique in near real time during wind-tunnel test operations is discussed
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