Industrial Technology Research Institute

Ji-Shang Yu

Yen-Chun Lin

Yung-Liang Huang

Chung Hsin Lu

June-Dan Shih

Ching-Hsiang Lin

Sammy Shyue

A one-bit differential detector for a GMSK signal operates independently of an offset frequency. In particular, a decision signal used by a decision circuit to distinguish between logic '0' and logic '1' is always equal to sin[.DELTA..phi.(T)]. The inventive detector has an improved bit error rate performance in comparison to the prior art.

One bit differential detector with frequency offset compensation

An apparatus and method for receiving a continuous time pulse amplitude-modulated passband signal is disclosed. The pulse amplitude modulated signal is periodically sampled by a local clock to generate received samples. A convolution of the received samples and an impulse response function is evaluated at a particular value of a phase difference variable to derive corrected samples. Using a narrow transmission band filter, a periodic signal is derived from the corrected samples. The periodic signal has a period equal to a symbol period of the pulse-amplitude modulated signal. Successive samples in each period of the periodic signal are compared to determine if the corrected samples lag or are ahead of optimal samples. If the corrected samples lag or are ahead of the optimal samples, the phase difference variable used to evaluate the convolution is varied by a fixed discrete stepsize.

Timing recovery method and system

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Taipei Hsien, Taiwan

Ji-Shang Yu