Abstract: A contact detection circuit is applied to a four-terminal measurement device. The contact detection circuit comprises a first isolator, a signal generator, a multiplier and a calculator. The first isolator comprises a primary side and a secondary side, with the secondary side comprising a first terminal and a second terminal, with the first terminal configured to be electrically connected to a driving terminal and the second terminal configured to be electrically connected to a measuring terminal. The signal generator is configured to provide a measuring signal. The multiplier is configured to generate an output signal based on the measuring signal and a first reflected signal when the first reflected signal is induced at the primary side of the first isolator based on the measuring signal. The calculator calculates contact resistance between the driving terminal and the measuring terminal based on a direct-current component of the output signal.

Abstract: A contact detection circuit is applied to a four-terminal measurement device. The contact detection circuit comprises a first isolator, a signal generator, a multiplier and a calculator. The first isolator comprises a primary side and a secondary side, with the secondary side comprising a first terminal and a second terminal, with the first terminal configured to be electrically connected to a driving terminal and the second terminal configured to be electrically connected to a measuring terminal. The signal generator is configured to provide a measuring signal. The multiplier is configured to generate an output signal based on the measuring signal and a first reflected signal when the first reflected signal is induced at the primary side of the first isolator based on the measuring signal. The calculator calculates contact resistance between the driving terminal and the measuring terminal based on a direct-current component of the output signal.

Abstract: A multiple access communication system in which receiving devices equipped with a method of differentiating signals from multiple users assigned with the same signature, the method comprising steps of determining a plurality of hypothetical signal levels according to a plurality of channel information; obtaining a pre-processed signal according to a received signal received by the receiving device, wherein the pre-processed signal comprises a mixture of a plurality of transmitted signals, and the transmitted signals are generated according to a plurality of signatures and encoded according to a plurality of data signals; calculating a plurality of symbol-level probabilities according to the pre-processed signal and the hypothetical signal levels, wherein the number of signatures may be less than the number of users; obtaining a plurality of log-likelihood ratios, corresponding to the users, and generating a plurality of decoded signals corresponding to the plurality of data signals according to the log-likeli