• The Journal of Korean Institute of Communications and Information Sciences
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• v.7 no.2
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• pp.47-54
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• 1982

In this paper, a improved per-channel PCM Coder with 1-bit interpolation is proposed. The coder converts a telephone signal to 15-segments u-law PCM signal of a large dynamic range. The A/D conversion technique of the proposed converter requires a feedback loop around a quantizer operates at high speed, and a accumulater for accumulating the quantized values to provide PCM outputs. To obtain both linear and compressed PCM signals a improved table look-up method is presented. The operations of the proposed converter are certified through the experiments to be good. The experimental circuit comprises TTL logic gates, a resistive D/Z converter and a simple differential amplifier. From the results of the experiments, it is known that the proposed converter has many advantage to be adopted economically for per-channel onverter used in rural area service.

• Proceedings of the IEEK Conference
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• summer
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• pp.77-81
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• 2004

In this paper, we propose a analog front-end (AFE) for noncoherent On-Off Keying (OOK) Ultra Wide Band (UWB) system based on power detection. The proposed AFE are designed using 0.18 micron CMOS technology and verified by simulation using SPICE. The proposed AFE consist of Sample-and-Hold block, Analog-to-Digital converter, synchronizer, delayed clock generator and impulse generator. The time resolution of 1ns is obtained with 100MHz system clocks and the synchronized 10-bit digital outputs are delivered to the baseband. The impulse generator produces 1ns width pulse using digital CMOS gates. The simulation results show the feasibility of the proposed UWB AFE systems.