Pseudo-atmospheric noise generator with control of temporal characteristics
First Claim
1. An improved pseudo-atmospheric noise generator for producing noise in the VLF/LF spectrum with known amplitude probability distributions while controlling the temporal characteristics of the impulses comprising:
- a plurality of pseudo-random bit generators having amplitude probability distribution outputs;
means coupled to receive the outputs from the pseudo-random bit generators for storing and selecting the outputs from the pseudo-random bit generators;
means coupled to the storing and selecting means for providing distribution of bursts of pulses representative of geographical temporal probability distributions for regional storms;
means coupled to the distribution providing means for converting digital pulses to analog signals of the random amplitude and distribution as determined by the distribution providing means;
a Gaussian noise source; and
means coupled to the analog signal converting means and the Gaussian noise source for summing the Gaussian noise signals and the analog signals in a selective ratio to provide the desired pseudo-random atmospheric noise signal.
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Abstract
An improved pseudo-atmospheric noise generator includes the capability forroducing noise in the VLF/LF spectrum with known amplitude probability distributions while controlling the temporal characteristics of the simulated impulses. The outputs from a number of pseudo-random bit generators are selected by a microprocessor in accordance with expected or anticipated atmospheric disturbances from a number of geographical regions. The microprocessor selected outputs are fed to a digital-to-analog converter which feeds the converted signals to a summer. An independent Gaussian noise source is coupled to the summer and the outputs from the Gaussian noise source and the digital-to-analog converter are combined to create a composite pseudo-atmospheric noise signal. The improvement also includes capability for self-testing and set up.
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Citations
10 Claims
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1. An improved pseudo-atmospheric noise generator for producing noise in the VLF/LF spectrum with known amplitude probability distributions while controlling the temporal characteristics of the impulses comprising:
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a plurality of pseudo-random bit generators having amplitude probability distribution outputs; means coupled to receive the outputs from the pseudo-random bit generators for storing and selecting the outputs from the pseudo-random bit generators; means coupled to the storing and selecting means for providing distribution of bursts of pulses representative of geographical temporal probability distributions for regional storms; means coupled to the distribution providing means for converting digital pulses to analog signals of the random amplitude and distribution as determined by the distribution providing means; a Gaussian noise source; and means coupled to the analog signal converting means and the Gaussian noise source for summing the Gaussian noise signals and the analog signals in a selective ratio to provide the desired pseudo-random atmospheric noise signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of creating a reference noise level signal for test purposes comprising:
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attenuating a predetermined Gaussian noise pattern at a preselected amplitude; passing the attenuated Gaussian noise pattern through a low pass filter and a wide dynamic range amplifier; and feeding the resultant signal through a bandpass filter having a known equivalent noise band width so that the Gaussian noise then establishes for the user a simulated atmospheric noise RMS level.
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Specification