Passband modulation 

Analog modulation 
Digital modulation 
Hierarchical modulation 
Spread spectrum 
See also 
Amplitude and phaseshift keying or asymmetric phaseshift keying (APSK) is a digital modulation scheme that conveys data by changing, or modulating, both the amplitude and the phase of a reference signal (the carrier wave). In other words, it combines both amplitudeshift keying (ASK) and phaseshift keying (PSK) to increase the symbolset. It can be considered as a superclass of quadrature amplitude modulation (QAM) because all QAM schemes are APSK schemes but some APSK modulation schemes have either all real or all imaginary symbols and therefore have either only an inphase component or just a quadrature component that can represent the whole symbol alphabet. The advantage over conventional QAM, for example 16QAM, is lower number of possible amplitude levels and lower PARP.^{[2]}
Moreover, a careful design of the constellation geometry can approach the Gaussian capacity as the constellation size grows to infinity. For the regular QAM constellations, a gap of 1.56 dB is observed.^{[3]} The previous solution, where the constellation has a Gaussian shape, is called constellation shaping.
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Generation and Detection of ASK, FSK and PSK part 1

Animation of Digital modulation  Amplitude, Frequency and Phase shift keying

ASK  FSK  PSK  DIGITAL MODULATION TECHNIQUES  BSNL JE (TTA)  BSNL JTO 
Transcription
References
 ^ "Standard + Customized APSK Schemes For Satellite Transmission" By Donald Vanderweit, Agilent Technologies, Inc.
 ^ Ershov, A.N., Berezkin, V.V., Petrov, S.V., Petrov, A.V. and Pochivalin, D.A., 2018. Features of Calculation and Design of HighSpeed Radio Links for Earth Remote Sensing Spacecraft.
 ^ H. Méric, Approaching The Gaussian Channel Capacity With APSK Constellations, IEEE Communications Letters.
Literature
 DVBFlexible Serially Concatenated Convolutional Turbo Codes with NearShannon bound performance for telemetry applications, CCSDS131.2O1.
 Xiang, Xingyu; Valenti, Matthew C (20121017). "Closing the Gap to the Capacity of APSK: Constellation Shaping and Degree Distributions". arXiv:1210.4831 [cs.IT].
 De Gaudenzi, R., Guillén i Fàbregas, A. and Martinez, A., 2006. Turbo‐coded APSK modulations design for satellite broadband communications. International journal of satellite communications and networking, 24(4), pp.261281.