Data archive files for "Reversal of Orbital Angular Momentum arising from an extreme Doppler shift," Gibson et al. PNAS 2018. Contents of "Reversal of OAM_Data Archive": ----------------------------------------------------------------------------------------------------------------------------------------------------------- Text file "Readme.txt" (this readme file) Labview program files (Created using National Instruments Labview 2014): Segment Acoustics Data.vi Average Segmented Data.vi Create Sonogram.vi Folder "Sub VIs for Create Sonogram program": Contains Labview application files used by "Create Sonogram.vi" - can generally be ignored by the user. Folder "MIC1": 221 *.bin files of the recorded signals from microphone 1. Folder "processed00_fmax0200" containing the processed data produced using the Labview program "Segment Acoustics Data.vi" with the above *.bin files. Folder "MIC2": 221 *.bin files of the recorded signals from microphone 2. Folder "processed00_fmax0200" containing the processed data produced using the Labview program "Segment Acoustics Data.vi" with the above *.bin files. ---------------------------------------------------------------------------------------------------------------------------------------------------------- Folders "MIC1" and "MIC2" contain the audio *.bin files as recorded by microphones 1 and 2 respectively. Each folder contains 221 files, one file for each rotation frequency of the microphone disk from 0Hz to 55Hz in 0.25Hz increments. The files follow the format: "fileNumb####_WheelSpin#.######Volt.bin", where fileNumb#### ranges between 0000 and 0220, and Wheelspin#.######Volt is the control voltage used to set the rotation frequency of the microphone disk. The relationship between the microphone rotation frequency and the control voltage is given by: Rotation(Hz) = (Volt - 0.05582)/0.05115 Each *.bin file contains 2,000,000 measurements of the microphone signal, recorded at a sampling rate of 96,000. In addition to the *.bin files, each of the above folders contains a folder called "processed00_fmax0200" which contains the processed files created using the "Segment Acoustics Data.vi" Labview program. "Segment Acoustics Data.vi" is a Labview program that takes each of the *.bin files in "MIC1" and "MIC2" and calculates the Fourier transform data. Each *.bin file, containing 2,000,000 measurements, is first divided into 20 segments of 100,000 measurements before the Fourier transform is calculated for each segment. The complex numbers from the Fourier transform are broken into their polar components and saved as two separate *.txt files, one containing the amplitude data and the other containing the phase data. The resulting *.txt files have the following format: "fileNumb####_WheelSpin#.######Volt_amplitude.txt" "fileNumb####_WheelSpin#.######Volt_phase.txt" Each *.txt file contains a matrix of size 20 x 208. This represents the Fourier transform data of the 20 individual audio segments, where each segment has 208 samples (interval of the 208 samples is 0.96Hz). "Average Segmented Data.vi" is a Labview program that averages the Fourier transform data from the 20 individual audio segments in the *txt files stored in the "processed00_fmax0200" folders within the "MIC1" and MIC2" folders. For each microphone rotation frequency, the average amplitude data is calculated for microphone 1, along with the average phase difference data between microphones 1 and 2. Two matrices are generated, one for the amplitude data and one for the phase data. The size of each matrix is 208 x 221 which represents the 208 discrete Fourier transform data samples and the 221 discrete rotation frequencies of the microphone disk. Also, individual Fourier spectra were saved to spreadsheet files in order to create Fig. 2(b) in the main manuscript. Here, the index control defined which of the 221 Fourier spectra was saved to disk. "Create Sonogram.vi" is a Labview program that plots the sonograms that appear in Fig. 2 of the main manuscript and Fig. 4 of the supplementary information. Here, the scaling of the data can be adjusted in addition to controlling the maping of colour to phase data.