Analysis of signals from the Dictabelt resolves a puzzling history of the acoustic evidence.

The loud brieftone that accompanied the Channel-II broadcast by Sergeant Bellah and its crosstalk onto Channel-I provides an unique opportunity to test the hypothesis of frequency compression that underlies the crosstalk analysis.

For decades students of the acoustic evidence have suspected that the crosstalk and tones became imprinted upon a dictabelt during copying a tape of the historic Dictabelt. Surprisingly, the NAS published clear and irrefutable evidence that they found the alleged Decker crosstalk on tape of a recopied dictabelt.

An unobvious characteristic of hearing caused many ear witnesses in Dealey Plaza to perceive echoes instead of the direct sounds of gunfire.

Many people assume that a motorcycle engine caused the background noise transmitted by the open microphone. An examination of the evidence shows these assumptions are without foundation. In fact the solitary analysis of the interference failed to detect engine sounds.

Engineers design two-way police radios for simultaneous operation with sirens.

On a single time scale an oscillograph lacks sufficient resolution to display the essential characteristics of human speech. When an oscillograph shows the intelligible portions of speech, it distorts the vocal characteristics. Under these conditions insufficient resolution produces the illusion that voice is a series of pulses. At the opposite extreme, magnifying the time scale to show vocal characteristics hides the slow changes that contain the intelligible speech.

The Ramsey Panel and the Watson Research Center used constant amplitude signals called brieftones from Channel-II to measure effect of heterodynes upon the gain of the Channel-I receiver. Spectral analysis shows both organizations misidentified Channel-II heterodynes as brieftones.

Analysis of the signals on the historic Dictabelt suggests that a studio added the acoustic signature of gunfire to distract researchers from the overwhelming strong evidence that a jammer was the source of the loud interference.

The loud brieftone that accompanied the Bellah crosstalk provides an opportunity to measure how Channel-I would have reproduced the brieftone that accompanied the Channel-II Decker broadcast."

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