Accession Number:

ADA089577

Title:

Spectograms Derived from Helicopter Blade Modulation Program

Descriptive Note:

Technical note 105-044

Corporate Author:

MARK RESOURCES INC SANTA MONICA CA

Personal Author(s):

• Mitchell, R. L.

Report Date:

1978-06-09

Pagination or Media Count:

7.0

Abstract:

A spectrogram is the output of a bank of filters e.g., an FFT as a function of time. It can be plotted as a 3-D surface, amplitude or power vs. frequency and time. The helicopter blade modulation signal as modeled in MRI- 149-19 and as simulated with the Fortran program was used to create several spectrograms. Author

Descriptors:

• *HELICOPTER ROTORS
• *ROTOR BLADES(ROTARY WINGS)
• *ELECTROMAGNETIC INTERFERENCE
• *SPECTROGRAPHY
• COMPUTERIZED SIMULATION
• GRAPHS
• FREQUENCY MODULATION
• FORTRAN
• FAST FOURIER TRANSFORMS
• DOPPLER EFFECT
• SINE WAVES
• WING TIPS
• SPECULAR REFLECTION

Subject Categories:

• Helicopters
• Test Facilities, Equipment and Methods
• Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE