Matsushita Electric Industrial Co., Ltd.

Masahiro Moriya

Makoto Sasaki

In a digital-to-analog converter comprising a pulse-width modulation signal generator for generating a pulse-width modulation signal by pulse-width modulating an actual set value with a count value, and a low-pass filter for removing a high frequency component of the pulse-width modulation signal so as to output an analog signal, a difference between a current target digital value and a previous target digital value are multiplied by a coefficient determined from a time constant of the low-pass filter and a cycle of the target set value, and the multiplied value is added to the previous target set value so as to calculate the actual set value.

Digital-to-analog converter and digital-to-analog converting method

Level crossing number counter section 115 obtains the Doppler frequency caused by fading by counting the number of times of a received signal crossing an averaged received signal level. Corresponding to the Doppler frequency, reference signal correlation integration control section 116 controls reference signal correlation integration section 311 to suspend and restart the processing of integrating the correlation data of the received signal obtained in reference signal correlation section 306 with a reference signal.

Reception apparatus

A CDMA communication system includes a base station and a mobile station. The base station transmits a first spread spectrum signal which contains information and a reference signal for synchronization. The mobile station receives the first spread spectrum signal from the base station. The mobile station includes a section for removing the reference signal from the received first spread spectrum signal and converting the received first spread spectrum signal into a second spread spectrum signal, and a section for despreading the second spread spectrum signal and recovering the information from the second spread spectrum signal.

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Yokohama, Japan

Masahiro Moriya