Search results
Results from the WOW.Com Content Network
Some pulse modulation schemes also allow the narrowband analog signal to be transferred as a digital signal (i.e., as a quantized discrete-time signal) with a fixed bit rate, which can be transferred over an underlying digital transmission system, for example, some line code. These are not modulation schemes in the conventional sense since they ...
the line-coded signal can be used to turn on and off a light source in free-space optical communication, most commonly used in an infrared remote control. the line-coded signal can be printed on paper to create a bar code. the line-coded signal can be converted to magnetized spots on a hard drive or tape drive.
Such systems are used in DTL (Direct To Line) and DFSG (Directly formed super group). 132 voice channels (2SG + 1G) can be formed using DTL plane the modulation and frequency plan are given in FIG1 and FIG2 use of DTL technique allows the formation of a maximum of 132 voice channels that can be placed direct to line. DTL eliminates group and ...
The guard interval also eliminates the need for a pulse-shaping filter, and it reduces the sensitivity to time synchronization problems. A simple example: If one sends a million symbols per second using conventional single-carrier modulation over a wireless channel, then the duration of each symbol would be one microsecond or less.
Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fraction of time according to agreed rules, e.g. with each transmitter working in turn.
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave.In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to that of the message signal, such as an audio signal.
After line coding, the signal can directly be put on a transmission line, in the form of variations of the current. The common types of line encoding are unipolar, polar, bipolar and Manchester encoding. Line coding should make it possible for the receiver to synchronise itself to the phase of the received signal. It is also preferred for the ...
It could be the transfer of an analog signal, using an analog modulation method such as frequency modulation (FM) or amplitude modulation (AM), or no modulation at all. Some textbooks also consider passband data transmission using a digital modulation method such as ASK, PSK and QAM, i.e. a sinewave modulated by a digital bit-stream, as analog ...