An Adaptive Manchester Decoder Design for Mobile Payment

Differential Manchester encoding is used for range-controlled communication. The deviation of the RC oscillator for decoding clock will lead to a higher decoding error rate. In this paper, the decoding signal is first filtered by the moving average filter to remove the glitches. In the data transform circuit, the square waves are transformed into triangular waves. On the triangular waves, the adaptive method is used to set high or low threshold levels, which decide the level of sampling signal. At the same time, the peak and the trough of the triangular wave are pointed to recovery clock and data, which are used for differential Manchester decoding. The experimental result demonstrate that this circuit is easily to implement and can decode differential Manchester code stably under the plus or minus 30% clock skew conditions at a reasonable cost.