Search results
Results from the WOW.Com Content Network
Morse code is called the original digital mode. Radio telegraphy, designed for machine-to-machine communication is the direct on / off keying of a continuous wave carrier by Morse code symbols, often called amplitude-shift keying or ASK, may be considered to be an amplitude modulated mode of communications, and is rightfully considered the first digital data mode.
A phase shift module is a microwave network module which provides a controllable phase shift of the RF signal. [ 1 ] [ 2 ] [ 3 ] Phase shifters are used in phased arrays . [ 4 ] [ 5 ] [ 6 ]
Alternatively, the phase shift of each symbol sent can be measured with respect to the phase of the previous symbol sent. Because the symbols are encoded in the difference in phase between successive samples, this is called differential phase-shift keying (DPSK). DPSK can be significantly simpler to implement than ordinary PSK, as it is a 'non ...
Dynamic – an array of variable phase shifters are used to move the beam; Fixed – the beam position is stationary with respect to the array face and the whole antenna is moved; There are two further sub-categories that modify the kind of dynamic array or fixed array. Active – amplifiers or processors are in each phase shifter element
A waterfall display depicting several PSK31 transmissions at around 14,070 kHz. The green lines indicate a station that is transmitting. PSK31 or "Phase Shift Keying, 31 Baud", also BPSK31 and QPSK31, is a popular computer-sound card-generated radioteletype mode, used primarily by amateur radio operators to conduct real-time keyboard-to-keyboard chat, most often using frequencies in the high ...
The resilience of APSK to amplifier and channel non-linearities afforded by its low PAPR have made it especially attractive for satellite communications, including DVB-S2. [3] A modified constellation diagram of 16-APSK. Typically 16-APSK will have 15 degree phase offset on the outer ring, which is not depicted here.
A once commonplace FDM system, used for example in L-carrier, uses crystal filters which operate at the 8 MHz range to form a Channel Group of 12 channels, 48 kHz bandwidth in the range 8140 to 8188 kHz by selecting carriers in the range 8140 to 8184 kHz selecting upper sideband this group can then be translated to the standard range 60 to 108 ...
Additionally, fine control of the beam direction can be provided with variable phase shifters in addition to the fixed phase shifters. [10] By using the variable phase shifters in combination with switching the power to the beam ports, a continuous sweep of the beam can be produced.