Apparatus and method for decoding information

A decoder, for decoding a predetermined encoded binary information stream wherein said encoded binary information stream varies between a first, second, third, and fourth input signal level, comprising:

• (a) differentiator means, having an input terminal adapted to receive said predetermined encoded binary information stream to provide a differentiated output signal;
• (b) comparator means, coupled to said differentiator means, and having a plurality of output terminals, for comparing said differentiated output signal to a plurality of predetermined levels to provide an output signal on respective output terminals when the amplitude of said differentiated output signal exceeds said predetermined levels, wherein said comparator means includes;
• a first, second, third, and fourth comparator each having a first and second input, the first input of each comparator operatively coupled to receive said differentiated output signal, and the second input of each comparator operatively coupled to a corresponding first, second, third, and fourth detection signal level, outputting said output signal on respective first, second, third, and fourth output terminals of said comparator when the amplitude of said differentiated output signal has exceeded the corresponding detection signal level;
• and
• (c) logic means, coupled to said plurality of output terminals, for decoding the output signals of said comparator means to provide a decoded signal, said decoded signal being a decoded binary information stream having a first and second level.