Abstract: An all-digital clock generator includes a digitally-controlled clock generator and a processing unit. The digitally-controlled clock generator generates a clock signal in response to an enable signal and a digital signal. The processing unit has a frequency multiplier and a reference signal having a period, digitizes the period to generate a quantized signal, generates the digital signal according to the quantized signal and the frequency multiplier, and generates the enable signal according to the reference signal, the clock signal and the frequency multiplier.

Abstract: The present invention provides a low-latency arc-tangent calculation structure and a calculation method thereof. The arc-tangent calculation structure comprises two lookup tables, a subtractor, a sign comparator, a numerical comparator and a shift encoder. The present invention divides the coordinate system into a plurality of sectors for simplifying the lookup tables. The first lookup table is used to perform logarithmic transformation so as to replace a divider with a subtractor. The second lookup table integrates an exponentiation table and an angle table to translate the output of the subtractor into arc-tangent value ?. Then, ? is shifted to a correct angle according to the output of the shift encoder.

Abstract: A cooperative apparatus and a frequency synchronization method thereof for use in a wireless network are provided. The wireless network comprises a base station and a subscriber station. The cooperative apparatus retrieves a signal from the base station and calculates a frequency offset between the base station and the cooperative apparatus according to the signal. Accordingly, the cooperative receives a cooperative information from the base station and forwards the cooperative information to the subscriber station based on the frequency offset.

Abstract: A MIMO detection method for a receiver in a MIMO system using N-QAM for modulation, the MIMO detection method including generating a plurality of symbol vector sets and a plurality of search radiuses, selecting a candidate symbol vector set corresponding to a highest level of a multilevel structure of N-QAM constellation, generating a search space corresponding to a lower level of the multilevel structure of N-QAM constellation according to the selected candidate symbol vector set, confirming which level the search space corresponds to, and generating a detection signal according to the search space when the level of the search space is the lowest level of the multilevel structure of the N-QAM constellation.

Abstract: A tangent angle computation device and associated DQPSK decoder. The computation device uses an eight-bit divider and a four-quadrant technique for finding a quantized angular value from an incoming signal. The quantized angular value is subsequently used to decode the incoming signal.

Abstract: A method of operating a matched filter of a point access memory (PAM) with variable lengths, suitable for a data storage region to store a received signal and for the matched filter to store a PN sequence in a storage region for reference values. The received signal comprises a plurality of sample data. The method of operating the matched filter of the PAM with variable lengths comprises: storing each sample data in the data storage region; shifting the PN sequence in the storage region for reference values to a corresponding position when all the sample data is stored in the data storage region; and performing a matching operation to match all the stored sample data and the PN sequence that are positioned in the corresponding position.

Abstract: A tangent angle computation device and associated DQPSK decoder. The computation device uses an eight-bit divider and a four-quadrant technique for finding a quantized angular value from an incoming signal. The quantized angular value is subsequently used to decode the incoming signal.

Abstract: A method and device for frequency synthesizing, in which the digital frequency synthesizer includes a clock pair having two similar ring-oscillators to separately generate a search frequency and an output frequency, a frequency tracking unit, and a clock controlling unit. The frequency-search method includes two stages: one stage is the coarse search stage based on the "Prune-and-Search", and other stage is the fine search stage based on the "fixed-step" algorithm. In order to determine which search scheme is used to search the target frequency and to determine the lock status, two cost functions for search and lock-in are derived. These two cost functions define the search threshold and the lock threshold, and these thresholds define the cost window and the lock window. If the frequency error is higher than both the search and lock thresholds, a coarse search is activated to estimate the correct frequency.