Signal Modulation Schemes

Analog Signal

Analog Data

• Amplitude Modulation (AM)
• Frequency Modulation (FM)
• Phase Modulation (PM)

Digital Data

• Phase Shift Keying (PSK)

  • Binary PSK (BPSK)
  • Quadrature PSK (QPSK)
  • 8PSK
  • 16PSK
  • Differential PSK (DPSK)
  • Differential QPSK (DQPSK)
  • Offset QPSK (OQPSK)
  • $\pi /4$ QPSK

• Frequency Shift Keying (FSK)

  • Audio Frequency Shift Keying (AFSK)
  • Multi-Frequency Shift Keying (MFSK)
  • Dual-tone Multi-Frequency (DTMF)

• Amplitude Shift Keying (ASK)

  • On-off Keying (OOK)

• Continuous Phase Modulation (CPM)

  • Minimum Shift Keying (MSK)
  • Gaussian Minimum Shift Keying (GMSK)
  • Continuous Phase Frequency Shift Keying (CPFSK)

• Orthogonal Frequency-Division Multiplexing (OFDM)

  • Discrete Multitone (DMT)

• Trellis Coded Modulation (TCM)

• Hierarchical Modulation

  • Quadrature Amplitude Modulation (QAM) (A combination of PSK and ASK)
    • Polar Modulation
  • Wavelet Modulation / Fractal Modulation

• Spread Spectrum Modulation Techniques

  • Direct Sequence Spread Spectrum (DSSS)
  • Chirp Spread Spectrum (CSS)
  • Frequency-Hopping Spread Spectrum (FHSS)
  • Time-Hopping Spread Spectrum (THSS)

Digital Signal

Analog Data

• Pulse Amplitude Modulation (PAM)
• Pulse Width Modulation (PWM)
• Pulse Phase Modulation (PPM)

Digital Data

• Pulse Code Modulation (PCM)

Images

ASK vs FSK vs PSK of a digital stream

Niche Use Cases

Satellites

These schemes are developed for satellites. They use analog signals to carry digital data.

NOTE

Synthesized BOC (SBOC) is used in NavIC satellites. Similarly,

• Composite BOC (CBOC) is used in Galileo
• Time-Multiplexed BOC (TMBOC) is used in GPS L1C

• Binary Offset Carrier (BOC) / Split-Spectrum Modulation
  • Sine BOC (sinBOC)
  • Cosine BOC (cosBOC)
  • Alternate BOC (altBOC)
  • Double BOC (DBOC)
  • Multiplexed BOC (MBOC)
    • Composite BOC (CBOC)
    • Time-multiplexed BOC (TMBOC)
    • Synthesized BOC (SBOC)

Notes

Binary Offset Carrier

See the Wikipedia page: Binary Offset Carrier | Wikipedia

Multiplexed BOC

Multiplexed BOC combines a sinBOC(1,1) signal with a sinBOC(6,1) signal, via either of CBOC or TMBOC Implemenation.

Synthesized BOC

Synthesized BOC Modulation Scheme is a non-linear combining method to generate constant envelope composite signal with MBOC (6,1,1/11) PSD.

It’s performance is similar to CBOC and TMBOC (Source: PowerPoint Presentation | unoosa.org)