Gaussian Minimum Shift Keying

GMSK is a popular modulation method, used in GSM, Hiperlan and DECT. It has a constant envelope, so it can be amplified using power-efficient non-linear (Class C) amplifiers.

Figure: power density spectra versus frequency normalize to user bit rate.

--- Solid line: GMSK The GMSK spectrum has a somewhat wider main lobe than BPSK, but sidelobes are much weaker. This reduces adjacent channel interference.

..... BPSK (The sinc-shaped spectrum)
- . - . QPSK (The QPSK spectrum is half a wide as the BPSK spectrum)

---	Solid line:	GMSK	The GMSK spectrum has a somewhat wider main lobe than BPSK, but sidelobes are much weaker. This reduces adjacent channel interference.
.....		BPSK	(The sinc-shaped spectrum)
- . - .		QPSK	(The QPSK spectrum is half a wide as the BPSK spectrum)

JPL's Wireless Communication Reference Website

Chapter: Analog and Digital Transmission. Section: Digital Modulation.

Gaussian Minimum Shift Keying

JPL's Wireless Communication Reference Website © Jean-Paul M.G. Linnartz, 1997.