| 摘要 |
METHOD AND APPARATUS FOR DECODING MANCHESTER ENCODED DATA A decoder for Manchester encoded data includes an up/down counter which constitutes a state machine. Consecutive bits with the same binary value in the encoded data bit stream enable the counter, which is incremented or decremented in dependence upon the relative phase of an output clock signal. Incrementing occurs in response to phase errors of the output clock signal, and decrementing to a count of zero occurs in response to phase assertions indicating a correct phase of the clock signal. The phase of the clock signal is reversed, and the counter reset, if a maximum count is reached in response to repeated phase errors. Such a phase reversal or phase slip is avoided in the presence of single bit errors in the bit stream. The decoded data is derived from the bit stream by sampling in dependence upon the clock signal. |
