A method of decoding a digital signal includes processing the digital using
a delay operation in accordance with a frequency characteristic of 1+D,
where D is an output signal of the delay element. The processed digital
signal is then converted to a three level conversion signal (0, positive,
negative). The conversion signal is then processed in accordance with a
frequency of 1/(1+D) to generate a decoded signal. The conversion signal
is also checked to determine if there is a conversion error. If a
conversion error is detected, propagation of the error is restricted, such
that a correct decoded signal is provided.
