A direct conversion receiver for GMSK in digital mobile communications

Quadrature detection is applied to the direct conversion receiver for a Gaussian minimum shift keying (GMSK) signal which is implemented by one DSP chip, TMS320C25, and some supporting components at the bit rate of 72 kb/s. The frequency error estimation, timing recovery, and decision are all completed by software, which makes the receiver simple and flexible. Computer simulation results and test performance of the actual system are satisfactory. The system is easy to modify for different requirements and is suitable for discrete realization and integration.