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.