Macronix International Co., Ltd.

Wen-Fu Yang

Hsan-Fong Lin

Jhy-Rong Chen

A pulse shaper for integrated service digital network (ISDN) U-interface. The pulse shaper of the present invention includes a couple of control clock generators, a clock-controlled fully differential switched-capacitor integrator, a fully differential sample and hold circuit, and a fully differential line driver/Rauch lowpass filter. The pulse shaper converts four-level 2B1Q digital input code (D0 and D1) to five staircase-type analog waveform by using fully differential switched-capacitor integrator. The sample and hold circuit then eliminates the spikes in the five-stair waveform and improve the signal linearity. The lowpass filter and telephone line driver is utilized to perform the output signal to comply with the waveform specification of ANSI T1 5.3.2.1 and 5.3.2.2.

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Hsinchu, Taiwan

Wen-Fu Yang