henri tajfel introduced the term in group and out group.
henri tajfel introduced the term in group and out group.
who introduced the term in group and out group?
henri tajfel
Na
Na
a second series of approaches was designed and patented by leonard r. kahn. the various kahn systems removed the hard limit imposed by the use of the strict log function in the generation of the signal. earlier kahn systems utilized various methods to reduce the second-order term through the insertion of a predistortion component. one example of this method was also used to generate one of the kahn independent-sideband (isb) am stereo signals. it was known as the str-77 exciter method, having been introduced in 1977. later, the system was further improved by use of an arcsine-based modulator that included a 1-0.52e term in the denominator of the arcsin generator equation. e represents the envelope term; roughly half the modulation term applied to the envelope modulator is utilized to reduce the second-order term of the arcsin "phase"-modulated path; thus reducing the second-order term in the undesired sideband. a multi-loop modulator/demodulator feedback approach was used to generate an accurate arcsin signal. this approach was introduced in 1984 and became known as the str-84 method. it was sold by kahn research laboratories; later, kahn communications, inc. of ny. an additional audio processing device further improved the sideband structure by selectively applying pre-emphasis to the modulating signals. since the envelope of all the signals described remains an exact copy of the information applied to the modulator, it can be demodulated without distortion by an envelope detector such as a simple diode. in a practical receiver, some distortion may be present, usually at a low level (in am broadcast, always below 5%), due to sharp filtering and nonlinear group delay in the if filters of the receiver, which act to truncate the compatibility sideband – those terms that are not the result of a linear process of simply envelope modulating the signal as would be the case in full-carrier dsb-am – and rotation of phase of these compatibility terms such that they no longer cancel the quadrature distortion term caused by a first-order ssb term along with the carrier. the small amount of distortion caused by this effect is generally quite low and acceptable.
single-sideband modulation