High level white noise generator

Patent · Mon Jan 01 00:00:00 EST 1979

OSTI ID:863455

Borkowski, Casimer J ^[1]; Blalock, Theron V ^[2]

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1. Oak Ridge, TN
2. Knoxville, TN

A wide band, stable, random noise source with a high and well-defined output power spectral density is provided which may be used for accurate calibration of Johnson Noise Power Thermometers (JNPT) and other applications requiring a stable, wide band, well-defined noise power spectral density. The noise source is based on the fact that the open-circuit thermal noise voltage of a feedback resistor, connecting the output to the input of a special inverting amplifier, is available at the amplifier output from an equivalent low output impedance caused by the feedback mechanism. The noise power spectral density level at the noise source output is equivalent to the density of the open-circuit thermal noise or a 100 ohm resistor at a temperature of approximately 64,000 Kelvins. The noise source has an output power spectral density that is flat to within 0.1% (0.0043 db) in the frequency range of from 1 KHz to 100 KHz which brackets typical passbands of the signal-processing channels of JNPT's. Two embodiments, one of higher accuracy that is suitable for use as a standards instrument and another that is particularly adapted for ambient temperature operation, are illustrated in this application.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• DOE Contract Number: W-7405-ENG-26
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4175258
• OSTI ID: 863455
• Country of Publication: United States
• Language: English

Related Subjects

level
white
noise
generator
wide
band
stable
random
source
well-defined
output
power
spectral
density
provided
accurate
calibration
johnson
thermometers
jnpt
applications
requiring
based
open-circuit
thermal
voltage
feedback
resistor
connecting
input
special
inverting
amplifier
available
equivalent
impedance
caused
mechanism
100
ohm
temperature
approximately
64
000
kelvins
flat
0043
db
frequency
range
khz
brackets
typical
passbands
signal-processing
channels
embodiments
accuracy
suitable
standards
instrument
particularly
adapted
ambient
operation
illustrated
application
spectral density
wide band
noise source
johnson noise
temperature operation
applications requiring
particularly adapted
ambient temperature
frequency range
output power
amplifier output
output impedance
random noise
feedback resistor
source output
density level
white noise
ohm resistor
processing channels
accurate calibration
/331/