attenuator


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at·ten·u·a·tor

(ă-ten'yū-ā-tŏr, -tōr),
1. An electrical system of resistors and capacitors used to reduce the strength of electrical signals, as in ultrasonography.
2. The terminator sequence in DNA at which attenuation occurs; located between the operator and the gene for the first protein in an operon.

attenuator

a regulatory NUCLEOTIDE sequence occurring in the LEADER REGION of an operon (see OPERON MODEL and containing a TRANSCRIPTION stop signal. The attenuator acts as a fine control mechanism for the activity of structural genes, sometimes being operative, sometimes not, depending on conditions in the cell.
References in periodicals archive ?
The Uludag Racing team has used a standard impact attenuator made from Impaxx 700 foam (Impaxx) and the weight is 700 gr.
Feeding network complexity Separate excitation Array patterns without sharing, 0% Sharing percentage, 20% Number of Peak SLL Number of Peak SLL attenuators (dB) attenuators (dB) Sum pattern N -24 N-N/4 -22 Difference pattern N -24 N -24 Total number 2N -- 2N-N/4 -- of attenuators Feeding network complexity Array patterns Sharing percentage, 50% Sharing percentage, 80% Number of Peak SLL Number of Peak SLL attenuators (dB) attenuators (dB) Sum pattern N-N/2 -16 N-3N/4 -15 Difference pattern N -24 N -24 Total number 2N-N/2 -- 2N-3N/4 -- of attenuators
However, since ROC ratios and attenuator values are determined by their geometries alone (for a given surface reflectance), they can be easily machined to achieve a wide range of splitter (or attenuator) values.
The Smith chart in Figure 6 illustrates the ideal paired complementary control signals (I/IN) for a balanced attenuator assuming four ideal equal split (that is, 3 dB) Lange couplers and four matched PHEMT devices.
A summary of promoter and attenuator mutations, as well as alterations in outer membrane profiles, is shown in Table 1 and Figures 1 and 2.
The operations manager for In-Line Traffic Marking Company's advocacy of truck-mounted attenuators saved the lives of two of the company's workers several years ago.
The low-power (calibrated levels from pW to 2W) 818 series detectors operate from 200 to 1800 nm and feature matching patented, removable OD3 attenuators for each photodetector.
MEMS-based solutions provider MEMSCAP (NYSE Euronext:MEMS) (Paris:MEMS) announced on Monday it has successfully completed die level reliability testing beyond 200m cycles on its Thermally Actuated Variable Optical Attenuators.
The power is varied by either adjusting the laser power itself (if the laser output power can be stabilized at all power levels) or by using a variable high-power laser attenuator. Ideally the output power stability should vary less than [+ or -] 0.5 % in any 15 min time period as laser power fluctuations directly affect the measurement uncertainty.
The new signal conditioning modular voltage attenuator system, or SCMVAS, is an analog signal conditioning system designed to safely monitor and accurately measure voltage potentials up to 1,200 V peak-to-peak.
Each channel has a modulation generator, a radio-frequency (RF) generator and an attenuator. The attenuator can simulate the threat scan and the range loss, as well as (if appropriate) the receiving-antenna pattern.
Another important element in this noise attenuator design is its conical exterior shape.