Limiting ratios between symbol rate and minimal carrier frequency in ultra-wideband digital information transmission systems
Limiting ratios between symbol rate and minimal carrier frequency f0 in ultra-wideband digital information transmission systems, when using rectangular pulse as the message symbol and transmission efficiencies of radio signal’s energy of 90 and 99% in the frequency band [0–2f0], are obtained. It is shown that modulation of sine and cosine oscillations by a rectangular pulse, in case of small number of carrier’s periods within the message symbol, gives different efficiency results of radio signal’s energy transmission in the provided frequency band. It is stated that, when using a rectangular pulse as message symbol and a requirement to transmit 99% of the radio signal’s energy in the frequency band [0–2f0], the maximal symbol rate of information transmission should be 12 times less than the carrier frequency. However, if transmission of 90% of the rectangular radio signal’s energy in the frequency band [0–2f0] is acceptable, the symbol rate of information transmission may exceed the minimal carrier frequency f0, but no more than 1.45 times.
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