Symbol quantization in interstellar communications: methods and observations

Abstract: Interstellar communication transmitters, intended to be discovered and decoded to information bits, are expected to transmit signals that contain message symbols quantized in at least one of the degrees of freedom of the transmitted signal. A hypothesis is proposed that signal quantization, in the form of multiplicative values of one or more signal measurements, may be observable during the reception of hypothetical discoverable interstellar communication signals. In previous work, using single and multiple synchronized radio telescopes, candidate hypothetical interstellar communication signals comprising delta-t delta-f opposite circular polarized pulse pairs have been reported and analyzed (ref. arXiv:2105.03727, arXiv:2106.10168, arXiv:2202.12791). In the latter report, an apparent quantization of delta-f at multiples of 58.575 Hz was observed. In the current work, a machine process has been implemented to further examine anomalous delta-f and delta-t quantization, with results reported in this paper. As in some past work, a 26 foot diameter radio telescope with fixed azimuth and elevation pointing is used to enable a Right Ascension filter to measure signals associated with a celestial direction of interest, relative to other directions, over a 6.3 hour range of Right Ascension. The 5.25 plus or minus 0.15 hour Right Ascension, -7.6 degrees plus or minus 1 degree Declination celestial direction presents repetition and quantization anomalies, during an experiment lasting 157 days, with the first 143 days overlapping the previous experiment.