The messages are either represented by a sequence of pulses by means of a line code ( " baseband transmission " ), or by a limited set of continuously varying wave forms ( " passband transmission " ), using a digital modulation method.
42.
It conveys two analog message signals, or two digital bit streams, by changing ( " modulating " ) the amplitudes of two carrier waves, using the amplitude-shift keying ( ASK ) digital modulation scheme or amplitude modulation ( AM ) analog modulation scheme.
43.
The German ( ITU Region 1 ) Amateur Radio Club ( DARC ) operates a propagation information beacon, under the non-amateur call sign "'DRA5 "'( JO44vq ), on 5195 kHz, which transmits in CW ( Morse code ) plus various digital modulation systems.
44.
Where " E " s is the energy per symbol in joules and \ rho is the nominal spectral efficiency in ( bit / s ) / Hz . " E " s / " N " 0 is also commonly used in the analysis of digital modulation schemes.
45.
Phase-shift keying ( PSK ) is a digital modulation scheme that conveys data by changing ( modulating ) the phase of a reference signal ( the carrier wave ) . The signal is impressed into the magnetic field x, y area by varying the sine and cosine inputs at a precise time.
46.
Digital communication systems : pulse code modulation ( PCM ), differential pulse code modulation ( DPCM ), delta modulation ( DM ); digital modulation schemes-amplitude, phase and frequency shift keying schemes ( ASK, PSK, FSK ), matched filter receivers, bandwidth consideration and probability of error calculations for these schemes.
47.
Of particular note is that many of the modern so-called " software defined radio " ( SDR ) transceivers have particularly slow AGC functions because of the latency created by the extensive digital signal processing ( A / D conversion, D / A conversion, digital filtering, digital modulation and digital demodulation ) used for the SDR implementation.
48.
Over 100 patents granted or in process, thirty years of experience in Research and Development at prominent institutions, and pioneering technologies such as the invention of the first digital cellular base station and fiber optic microcell utilizing high power linear amplifier technology and digital modulation techniques, which allowed the beginning of the digital cellular evolution, digital cellular standards, personal communications networks as well as the emergence of Mobile Cloud Computing within 4G broadband wireless networks.
