Search results
Results from the WOW.Com Content Network
Amplitude and phase-shift keying (APSK) is a digital modulation scheme that conveys data by modulating both the amplitude and the phase of a carrier wave. In other words, it combines both amplitude-shift keying (ASK) and phase-shift keying (PSK).
Phase-shift keying (PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency carrier wave.The modulation is accomplished by varying the sine and cosine inputs at a precise time.
Amplitude-shift keying (ASK) is a form of amplitude modulation that represents digital data as variations in the amplitude of a carrier wave. [1] In an ASK system, a symbol , representing one or more bits , is sent by transmitting a fixed-amplitude carrier wave at a fixed frequency for a specific time duration.
The peak amplitude and the frequency of the carrier signal are maintained constant, but as the amplitude of the message signal changes, the phase of the carrier changes correspondingly. Phase modulation is an integral part of many digital transmission coding schemes that underlie a wide range of technologies like Wi-Fi , GSM and satellite ...
Each symbol is encoded as a different phase shift of the carrier sine wave: 0°, 45°, 90°, 135°, 180°, 225°, 270°, 315°. A constellation diagram is a representation of a signal modulated by a digital modulation scheme such as quadrature amplitude modulation or phase-shift keying. [1]
Several keying techniques exist, including phase-shift keying, frequency-shift keying, and amplitude-shift keying. Bluetooth, for example, uses phase-shift keying to exchange information between devices. An overview of keying techniques is given at Modulation § Fundamental digital modulation methods
The two amplitude-modulated sinusoids are known as the in-phase (I) and quadrature (Q) components, which describes their relationships with the amplitude- and phase-modulated carrier. [ A ] [ 2 ] Or in other words, it is possible to create an arbitrarily phase-shifted sine wave, by mixing together two sine waves that are 90° out of phase in ...
On–off keying (OOK) denotes the simplest form of amplitude-shift keying (ASK) modulation that represents digital data as the presence or absence of a carrier wave. [1] In its simplest form, the presence of a carrier for a specific duration represents a binary one, while its absence for the same duration represents a binary zero.