вторник, 1 сентября 2009 г.

The small series of the articles about Scramblers by MSM Group.

Public conventional Scramblers. Part I.
Icom UT-109.
The static double-band analogue scrambler.

Author: SergUA6 6.0
Band Width ~3400 Hz
RX mode NFM

The Scrambler is

Icom UT-109 - the static double-band analogue scrambler. An operation principle of it is easily defined on the sonogram. The initial spectrum of speech is divided/separated on two parts, by the
conditional/relative line (frequency),and each part is inverted. The breaking line of the spectrum is an original key.

Listening Resistance is much more lower than for scrambler Icom UT-110, and generally comes nearer to direct inversion, and do not exceeding direct inversion so much.

The ear is extremely powerful analyzer oriented on speech, and loss even half of spectrum on the good signals does not lead to disastrous loss of articulation, especially if the language is native and the subject of the speech is not strongly specific.

The widespread enough error is that scrambler UT-109 represents itself
the direct inversion.

In reality, in very many cases, it is really possible rather successfully to de-scramble this masking/mask as direct inversion, especially if the second half of spectrum is rather narrow. For example as on the first, second or fourth fragment in the record, but for the qualitative and a complete recovery the special approach with taking into account features of the scrambling is necessary.