Semiconductor Manufacturing International (shanghai) Corporation

Semiconductor Manufacturing International (beijing) Corporation

Spreadtrum Communications (shanghai) Co., Ltd.

Jiaqing Wang

Wenzhe Luo

Jiangang Wu

Qingyang Wu

Haifeng Shen

Yunxiang Peng

A converting circuit and a communication device are provided. The converting circuit includes: a sample hold circuit for receiving an analog signal; a Digital to Analog Converter (DAC); a comparator being connected with an output end of the sample hold circuit and an output end of the DAC; and a control circuit being connected with an output end of the comparator, wherein when the sample hold circuit receives an analog signal, the control circuit controls the sample hold circuit and the comparator to work, controls an output of the DAC based on an output of the comparator, and outputs a corresponding digital signal; and when the control circuit detects a digital signal is input, the control circuit controls the DAC to convert the digital signal into an corresponding analog signal and output the corresponding analog signal. The converting circuit can reduce chip area and chip cost.

Converting circuit with control circuit to detect signals input into the converting circuit, and communication device

A demodulation circuit for an Amplitude Shift Keyed (ASK) modulated signal includes an envelope detector, an alternating voltage amplifier, a differentiator circuit, and a comparator having a hysteresis connected in series. The envelope detector produces an envelope signal from the received ASK signal. The amplifier blocks the DC component of the envelope signal and amplifies AC components of the envelope signal to obtain a steeper slope of the rising and falling edges. The differentiator circuit then processes the transition edges to provide a differentiated signal having positive and negative electrical pulses. The comparator converts the pulses into a binary data stream which corresponds to the transmitted data stream. The combination of the differentiated signal and comparator having a hysteresis enables better stability and sensitivity of the ASK demodulation circuit.

Amplitude shift keyed (ASK) demodulation pattern and use in radio frequency identification (RFID)

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Shanghai, China

Jiaqing Wang