TY - JOUR
AB - MR. P. P. ECKERSLEY in a paper read to the Institution of Electrical Engineers on March 2 said that the present methods of working permit few, except local radio broadcasting stations to be received without interference from other transmitters operating in contiguous frequency channels, unless the upper frequencies of modulation of the wanted station are severely attenuated. In this case the reproduction lacks intelligibility and naturalness. This can be mitigated without introducing audible harmonic distortion by utilizing the asymmetric sideband system of transmission to cut away with the aid of electrical filter circuits part of one sideband of the frequency spectrum radiated. In a previous paper, the author has shown how ‘asymmetry’, either of phase or of magnitude, between two sideband components is related to harmonic distortion. It is proportional to depth of modulation. He proved that as the sideband frequency becomes more and more removed from the carrier frequency, it may be more and more attenuated while the distortion can be made to remain constant and small. The author suggests that it is better to face the occasional minute deteriorations in quality given by the asymmetric system than to suffer from the continuous hissing and splitting sounds brought about by existing inter-station interference. The public insists that the radio-set exists to give pleasure. The attention that a user gives to a programme is determined partly by the quality of reproduction, but probably more by the freedom it enjoys from interference from extraneous sounds. It is primarily programme interest which pleases, but interference is very objectionable however good the programme. The author acknowledges his thanks to the B.B.C. for providing the funds for the construction of test apparatus. He also thanks the Countess von Zeppelin for her mathematical investigation, given in an appendix, resulting in a most useful expression for the distortion component.
TI - Asymmetric Sideband Broadcasting
JF - Nature
DO - 10.1038/141442c0
DA - 1938-03-12
UR - https://www.deepdyve.com/lp/springer-journals/asymmetric-sideband-broadcasting-d5Wa08W3kn
SP - 442
EP - 443
VL - 141
IS - 3567
DP - DeepDyve
ER -