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The Concept uses Frequency Shift ing, in order to overcome the Narrow Bandwidth of regular telephone systems. The Input Signal is sent to one telephone line as-is, or in some cases upshifted to provide extra low-frequency response, and sent to a second line shifted down by 3 KHz , which is normally the upper Bandpass limit in telephony. Thus, an audio frequency of 5 kHz is sent at 2 kHz. A receiver on the other end then shifts the second line back up and Mixes it with the first. This results in greatly improved audio, adding a full Octave of range, and pushing the total bandpass to 6 kHz. The sound is then acceptable for Voice , if not for Music . It is also possible to add other lines, each increasing the bandpass by another 3 kHz. However, the Law Of Diminishing Returns takes over, because each successive octave is double the size of the last. A third line pushes the bandpass up 50 % to 9 kHz, equivalent to AM Radio . A fourth line would push it up 33% to 12 kHz. FM Radio quality would require five telephone lines to be installed, pushing the bandpass up 25% to 15 kHz. The audio is shifted down by 6,9, and 12 kHz respectively for each additional line. SEE ALSO |
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